LIBRARY 

UNIVERSITY  OP 
V      CALIFORNIA 


THE  COMPOUND  LOCOMOTIVE 


SUPPLEMENT  TO 


THE  SCIENCE  OF  RAILffAIS. 


BY 

MARSHALL  M.  KIRKMAN. 


THIS    SUPPLEMENT    IS    RESPECTFULLY    PRESENTED    BY   THE    WORLD 
RAILWAY    PUBLISHING    COMPANY    TO    SUBSCRIBERS    TO 
THE  EIGHTH  EDITION  OF  "THE  SCIENCE  OF  RAIL- 
WAYS" AND  IS  DESIGNED  TO  FORM  A  PART 
OF  THE  "ENGINEERS' AND  FIREMEN'S 
MANUAL,"  VOLUME  XII. 


EIGHTH  EDITION. 


NEW  YORK  AND  CHICAGO: 

THE  WORLD  RAILWAY  PUBLISHING  COMPANY. 
1899 


LOAN  STACK 


COPYRIGHT  Br 

THE  WORLD  RAILWAY  PUBLISHING  COMPANY, 


The  Regan  Printing  House,  Chicago. 


CHAPTER  T. 

ENGINEERS'  AND  FIREMEN'S  MANUAL,  CONTINUED- 
COMPOUND   LOCOMOTIVES INTRODUCTORY. 


NOTE — In  regard  to  the  merits  of  the  compound  cylinder  as 
compared  with  the  single-expansion,  I  do  not  desire  nor  profess 
to  express  any  opinion.  I  merely  wish  to  describe  the  compound 
cylinder  in  what  follows,  and,  if  in  some  places  preference  seems 
to  be  expressed,  it  is  the  claim  of  builders  and  not  mine.  Those 
who  use  locomotives  must  themselves  be  the  judges  of  the  re- 
spective merits  of  single-expansion  and  compound  cylinders  and 
of  the  particular  pattern  they  want. 

January,  1899.  M.  M.  K. 

In  view  of  the  fact  that  the  Compound  Loco- 
motive is  of  comparatively  recent  introduction  as 
compared  with  the  single-expansion  cylinder,  its 
construction  and  working  are  less  understood  by 
those  connected  with  the  equipment  department 
of  railroads.  These  particulars  I  have,  for  that 
reason,  thought  it  best  to  embody  here  in  con- 
nection with  the  "ENGINEERS'  AND  FIREMEN'S 
MANUAL."  More  and  more  attention  is  being 
given  to  the  expansive  use  of  steam  in  connection 
with  the  locomotive.  It  is  claimed  not  to  be  un- 
reasonable in  view  of  the  triple  and  the  quadruple 
expansion  of  steam  (expansion  in  three  and  four 
cylinders)  in  the  most  approved  stationary  and 
marine  engines  that  it  should  be  possible  to  de- 
vise practical  means  of  obtaining  double  expan- 

(3) 


865 


4  tiNGINEEffl*  AND  FIREMEN'S  MANUAL. 

sion,  at  least,  in  a  locomotive.  Because  of  the 
more  or  less  general  introduction  of  compound 
cylinders,  some  account  of  the  working  of  the  com- 
pound locomotive  is  becoming  every  day  more 
and  more  necessary  to  those  connected  with  the 
machinery  and  equipment  of  railroads.  Indeed, 
practical  familiarity  with  the  working  of  com- 
pound engines  may  be  said  to  have  become,  in  a 
measure,  a  necessary  part  of  the  knowledge  of 
every  engineer  and  fireman,  for  the  reason  that 
their  duties  may  at  anytime,  through  promotion 
or  otherwise,  take  them  to  roads  where  some 
form  of  compound  locomotive  is  extensively  used. 
Moreover,  it  is  well  that  their  attention  be  espe- 
cially directed  to  the  subject  in  order  that  it  may 
have  the  consideration  and  scrutiny  at  their 
hands  which  its  growing  importance  justifies  and 
their  practical  knowledge  is  likely  to  render  so 
valuable. 

It  is  not  surprising,  inasmuch  as  the  opinions 
of  engineers  and  firemen  respecting  the  opera- 
tion of  simple  engines  differ  so  widely,  that  there 
should  be  much  controversy  among  them  in  re- 
gard to  the  operation  of  compound  locomotives. 
Experience  on  the  part  of  those  operating  the 
compound  locomotive  will  tend  to  its  better 
service  and  consequently  greater  development. 
Many  prejudices  against  it  are  due  to  lack  of  ac- 
quaintance with  its  operation.  This  is  true  of 
every  new  thing.  Especially  is  it  true  in  the 
case  of  compounds  where  a  railway  has  few  loco- 
motives of  this  kind.  The  feeling  is  but  natural, 
if  we  remember,  as  we  should,  that  in  the  handling 


COMPOUND  LOCOMOTIVES.  5 

of  their  engine  the  reputation  of  the  engineer 
and  fireman  is  at  stake.  The  opportunity  af- 
forded them  for  handling  and  studying  any  odd 
engine,  compound  or  otherwise,  is  necessarily 
limited.  Moreover,  in  the  operation  of  such  lo- 
comotive, it  is  possible  they  may  be  impressed 
with  the  unhandy,  because  unusual,  cab  arrange- 
ments. Naturally,  they  are  filled  with  appre- 
hension, lest  some  accident  might  occur  and 
they  be  found  ignorant  of  what  should  be  done 
to  temporarily  repair  the  engine  and  bring  it  in. 
If  a  considerable  number  of  the  locomotives  of  a 
railroad  are  compounds  of  similar  class,  the  men 
handling  them  become  accustomed  to  their  opera- 
tion and  this  fear  disappears.  It  is  with  a  view 
to  the  practical  usefulness  these  pages  may  have 
for  engineers,  firemen,  and  others  interested  in 
the  operation  of  compounds,  that  the  descrip- 
tions herein  are  elaborated  to  the  extent  they  are. 
The  plan  followed  with  each  class  of  compound 
locomotives  is,  first,  to  give  a  general  description 
of  its  operation,  succeeded  by  a  detailed  descrip- 
tion of  its  technical  parts.  This  is  done  that  the 
reader  may,  in  the  first  instance,  if  he  desires, 
learn  of  the  general  arrangement  of  each  class 
without  the  details,  and  afterwards,  at  his  leisure, 
he  may  apply  himself  to  the  particular  class  or 
classes  that  most  interest  him.  Following  the 
description  of  each  class  of  compounds  will  be 
found,  in  catechetical  form,  information  relating 
to  its  operation  in  case  of  any  ordinary  derange- 
ment of  its  parts  when  the  methods  of  procedure 
will  differ  from  those  in  case  of  similar  accidents 


6  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

to  simple  locomotives,  as  outlined  in  the  manual. 
It  is  said  that  reforms  must  pass  through 
three  stages:  ridicule,  argument,  and  adoption. 
The  compound  has  been  subjected  to  the  first 
and  second  of  these  epochs,  and  it  may  be  as- 
sumed to  have  reached  the  last  stage  mentioned. 
Like  every  part  of  a  railroad,  it  is  still  in  a  state  of 
evolution.  I  know  of  no  preference  in  regard  to 
compounds  that  is  proper  to  express  here.  The 
order  of  description  has,  therefore,  no  signifi- 
cance. In  the  description  of  the  various  types  I 
have  endeavored  to  eliminate  all  matter  that 
does  not  pertain  directly  to  the  practical  appli- 
cation of  the  principle  of  compounding,  as  de- 
scriptions relating  to  other  parts  of  the  locomo- 
tive are  to  be  found  elsewhere  in  "THE  SCIENCE 
OF  RAILWAYS."  In  relation  to  the  descriptions 
of  the  compound,  I  wish  to  say  that  I  am  in- 
debted in  a  marked  manner  to  Mr.  E.  W.  Pratt, 
whose  familiarity  with  the  construction  and 
working  of  locomotives  and  the  appliances  of  the 
latter  makes  him  an  authority  of  the  highest  or- 
der in  regard  to  all  such  matters.  I  am  in- 
debted to  him  in  many  other  ways  and  it  affords 
me  much  gratification  to  be  able  to  acknowledge 
it  thus  conspicuously. 


CHAPTEE  II. 
ENGINEERS'    AND    FIREMEN'S    MANUAL  —  COMPOUND 

LOCOMOTIVES GENERAL      DESCRIPTION COM- 
PARISON   WITH    SIMPLE    LOCOMOTIVES. 

A  compound  locomotive  is  one  in  which  the 
exhaust  from  one  or  more  cylinders  is  passed 
into  one  or  more  other  cylinders  and  made  to  do 
more  work  by  further  expansion  before  it  is  al- 
lowed to  escape  to  the  atmosphere.  In  stationary 
and  marine  service  the  principle  of  compounding 
has  long  since  passed  its  experimental  stage  and, 
following  the  replacement  of  the  single-expansion 
engine  by  the  double-expansion  type,  came  the 
era  of  high  boiler  pressures  with  triple  and  even 
quadruple-expansion  engines  in  marine  service. 
It  was  long  thought  by  many,  and  is  still  held 
by  some,  that,  although  compounding  of  steam 
in  marine  and  stationary  engines  was  a  great 
economy  due  to  the  use  of  the  condenser,*  on 
locomotives  where  condensers  were  impractic- 
able, the  compound  locomotive  would  not  be  able 
to  gain  sufficient  advantage  over  the  simple 
engine  to  warrant  their  general  use. 

Without  any  attempt  to  pass  judgment  upon 
the  relative  value  of  the  points  put  forward  for 
and  against  compound  locomotives,  I  will  out- 


*A  condenser  is  a  chamber  into  which  the  final  exhaust  of  an 
engine  takes  place  and  in  which  the  steam  is  cooled  and  con- 
densed, either  by  a  jet  of  water  or  by  contact  with  sheets  or 
tubes  having  cold  water  circulation  on  their  opposite  sides. 
These  two  forms  of  condensers  are  termed  "jet  condenser"  and 
"surface  condenser,"  respectively. 

(7) 


8  EXGIXEERS'  AXD  FIREMEN'S  MANUAL. 


line  some  of  the  claims  made  by  their  advocates 
and  also  some  of  the  practical  objections  met 
with  in  their  use,  many  of  which  objections 
have  been  largely  overcome-  in  the  later 
designs. 

It  should  be  remembered  that  the  locomotive 
is  not  a  steam  engine  merely,  but  consists  of  a 
boiler  as  well,  and  must  also  carry  water  and  fuel 
for  its  own  demands. 

The  first  advantage  of  the  compound  over  the 
simple  locomotive  comes  from  its  greater  economy 
in  fuel,  resulting  primarily  from  the  saving  in 
steam.  There  is,  however,  a  secondary  saving,  pro- 
duced by  the  less  violent  effect  of  the  exhaust  upon 
the  fire  and  also  the  economical  use  of  high  boiler 
pressures  in  compound  engines. 

Experiments  have  shown  that  high  boiler  pres- 
sures, say  above  180  pounds,  which  have  been 
found  very  economical  (especially  in  the  space 
occupied  per  horse  power  developed)  in  station- 
ary and  marine  engines,  are  not  a  source  of  econ- 
omy with  the  type  of  single-expansion  locomotives 
in  use  in  this  country,  due  to  the  extreme  ranges 
of  temperature  within  a  single  cylinder  and  the 
consequent  condensation.  Also,  locomotive  cylin- 
ders and  their  steam  ports  are  not  well  protected, 
and  compounding  the  cylinders  renders  the  varia- 
tions of  temperature  in  each  cylinder  less  wide, 
and  thus  makes  practicable  the  use  of  higher  pres- 
sure. With  the  use  of  steel  in  place  of  iron  for 
boiler  construction,  and  also  on  account  of  the 
excellent  care  and  inspection  given  all  locomo- 
tive boilers,  there  is  no  material  increase  of  first 


COMPOUND  LOCOMOTIVES.  9 

cost  or  for  maintenance  of  high-pressure  boilers. 
In  simple  locomotives  the  exhaust  produces 
such  a  violent  draft  upon  the  fire  that  great 
quantities  of  unconsumed  fuel  are  drawn  from 
the  fire-box  and  thrown  from  the  stack.  This  is 
not  alone  a  waste  of  fuel,  but  cinders  entering 
the  open  car  windows  are  a  source  of  great  an- 
noyance to  passengers,  while,  before  the  use  of 
the  compound  locomotive  in  the  service  of  subur- 
ban railways,  the  noise  of  the  exhaust  had  to  be 
overcome  by  means  of  mufflers,  which  became 
quickly  choked  up  and  produced  a  high  back- 
pressure on  the  pistons,  resulting  in  the  loss  of 
from  15  to  20  per  cent,  of  the  power. 

The  throwing  of  sparks  from  the  stack  is  not 
only  a  source  of  annoyance,  but  frequently  re- 
sults in  heavy  losses  from  damage  by  fire  in  tim- 
ber and  agricultural  districts,  and  this  is  largely, 
if  not  entirely,  overcome  by  the  compound 
locomotive. 

The  heating  surfaces  of  any  given  boiler  absorb 
heat  from  the  fire  and  deliver  it  to  the  water  at 
a  certain  rate.  If  the  rate  at  which  the  products 
of  combustion  are  carried  away  exceeds  this  rate 
of  absorption,  there  will  be  a  continual  waste 
that  can  only  be  overcome  by  reducing  the  veloc- 
ity of  the  products  of  combustion.  In  the  com- 
pound locomotive  this  is  effected  by  the  milder 
exhaust.  It  has  been  clearly  demonstrated  by 
experiment,  that  a  milder  exhaust  and  conse- 
quently a  slower  rate  of  combustion  produces  a 
greater  evaporation  of  water  per  pound  of  fuel. 

The  milder  exhaust  is,  of  course,  the  result  of  a 


10 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


lower  back-pressure  and  thereby  permits  a  greater 
effective  power  on  the  piston. 

There  is  also  found  to  be  considerable  reduction 
in  cylinder  condensation,  owing  to  the  relatively 
small  variation  of  temperatures  in  each  cylinder 
as  compared  with  single-expansion  engines.  In 
any  engine  the  walls  of  the  cylinder,  one  cylinder- 
head,  and  one  side  of  the  piston  are  cooled  to  the 
temperature  of  the  exhaust  steam  during  each 
stroke,  and  the  live  steam,  again  entering,  must 

Fig.  100. 

4  StroKt  £.&n>Ke  -  $StroKe  fuUStrakt 


I 
_;2o 


LENGTH  or  STROKE 


reheat  them  to  its  own  temperature,  thus  con- 
densing and  requiring  additional  steam  to  flow  in 
and  take  its  place.  In  the  compound  this  total 
range  of  temperature  is  divided  between  the  high 
and  the  low-pressure  cylinders,  and  thus  the  vari- 
ation and  consequent  condensation  in  each  cylin- 
der is  less. 

The  saving  of  steam  results  in  the  saving  of 


COMPOUND  LOCOMOTIVE*.  11 

both  water  and  fuel.  The  economy  in  fuel  can 
be  directly  reduced  to  dollars  and  cents,  while 
that  resulting  from  the  saving  of  water  is  more 
indirect.  In  bad  water  districts,  the  reduction 
of  from  15  to  20  per  cent,  in  the  amount  of  water 
used,  necessitates  less  frequent  washings-out  of 
the  boiler  and  must  result  in  greater  life  and 
diminished  repairs  to  boiler  and  flues.  Moreover, 
as  its  carrying  capacity  of  water  limits  the  dis- 
tance that  a  locomotive  can  run  without  stopping 
(or  slowing  up,  where  track-tanks  are  used),  it  is 
evident  that  the  compound  locomotive  would  have 
an  advantage  in  this  respect.  Fig.  100,  besides 
showing  the  most  economical  point  of  cut-off  for 
simple  and  compound  engines,  as  far  as  the  use 
of  water  is  concerned,  clearly  shows  the  relatively 
smaller  amount  of  water  used  by  the  compound 
per  indicated  horse  power. 

No  locomotive  can  haul  more  than  its  adhesion 
to  the  rails  will  permit,  and  hence  the  tractive 
power  of  an  engine  is  based  upon  whatever  the 
adhesion  to  the  rails  may  be.  This  is  determined 
by  practical  experiment.  With  a  fairly  dry  rail, 
a  turning  force  of  more  than  one-fifth,  or  20  per 
cent.,  of  the  weight  of  the  drivers  on  the  rails, 
will  cause  the  wheels  to  slip;  a  perfectly  dry  rail 
will  permit  of  a  tractive  power  of  about  one- 
fourth,  or  25  per  cent.,  of  the  weight  on  the 
drivers;  a  well  sanded  dry  rail  will  allow  one- 
third,  or  33^  per  cent.,  while  a  bad  frosty  rail 
will  permit  less  than  half  this  last  amount. 
Where  all  the  driving  wheels  are  connected,  it 
matters  not,  -of  course,  whether  this  force  is  ap- 


12  ENGINEERS'  AND  FIREMEN\*  MANUAL. 

plied  by  one  or  many  cylinders,  but,  if  the  power 
is  not  uniformly  distributed  throughout  the  revo- 
lution and  becomes  sufficiently  excessive  at  any 
one  point  to  cause  the  wheels  to  slip,  a  very 
much  less  power  will  thereafter  keep  them  slip- 
ping. It  is  a  well  known  fact  that  adhesion,  and 
consequently  the  tractive  power  of  a  locomotive, 
is  verv  much  reduced  after  the  wheels  begin  to 
slip.*" 

It  is  claimed  for  the  compound,  that,  as  the 
average  cut-off  is  later  in  both  cylinders  than  for 
simple  engines,  the  turning  power  is  more  uni- 
form throughout  the  revolution,  and  hence  heavier 
trains  can  be  hauled  than  with  the  single-expan- 
sion engine.  Then,  too,  while  it  would  be  un- 
economical at  other  times  to  design  a  simple 
engine  with  cylinders  sufficiently  large  to  develop 
so  high  a  tractive  power  as  33^  per  cent,  at  slow 
speeds,  this  can  be  done  with  compound  loco- 
motives of  the  "convertible"  type  without  loss 
in  economy  under  ordinary  speeds  of  service, 
when  working  compound. 

A  saving  of  oil  has  been  one  of  the  minor  econ- 
omies claimed  to  be  incidental  to  the  use  of  com- 
pound locomotives.  It  is  generally  thought  that 
from  six  to  ten  drops  of  valve  oil  per  minute  are 
required  to  be  supplied  with  the  steam  in  order 
to  properly  lubricate  a  valve  and  cylinder.  This 


*Every  engineer  knows  this  and  puts  his  knowledge  into  prac- 
tice when  on  a  very  slippery  rail  by  opening  the  throttle  very 
slightly  and  leaving  the  valve  in  full  gear,  thus  distributing  the 
pressure  more  uniformly  throughout  the  stroke  than  would  be 
the  case  with  a  shorter  cut-off, 


COMPOUND  LOCOMOTI VES.  1 3 

oil  is  supplied  to  the  high-pressure  cylinder  only, 
and  hence,  in  the  two-cylinder  class  of  com- 
pounds, a  saving  has  been  effected  in  many  cases. 

Comparative  tests  of  greater  or  less  duration 
have  been  made  by  various  railways,  between 
compound  and  simple  locomotives  of  otherwise 
similar  construction,  and  the  results  obtained  by 
the  different  experimenters  are  widely  at  vari- 
ance. In  general,  it  may  be  said  that  the  re- 
ported saving  in  fuel  with  the  compound  is  about 
ten  per  cent,  in  fast  passenger  and  20  per  cent, 
in  heavy  freight  service,  although  figures  double 
the  latter  have  frequently  been  given.* 

Later  designs  of  compound  locomotives,  arranged 
to  be  worked  simple  at  the  will  of  the  engineer,  will 
temporarily  pull  a  heavier  train  than  a  simple 
engine  of  otherwise  like  design.  When  it  is  con- 
sidered that  the  ruling  grade  on  a  division  is  the 
governing  factor  for  the  maximum  rating  of 
through  trains  over  the  whole  division,  it  will  be 
seen  that  a  locomotive  capable  of  enough  greater 
power  to  haul  an  additional  car  or  two  up  that 
grade,  produces  more  economical  service  for  the 
whole  division. 

Leaky  valves  and  cylinder  packing  are  less 
wasteful  in  a  compound  than  in  a  simple  engine. 
Steam  leaking  by  the  valve  or  packing  of  the 
high-pressure  cylinder  is  still  worked  expansively 


*Fast  freight  service  will  more  nearly  compare  with  express 
passenger  service  and  the  saving  will  be  less  than  in  heavy  slow 
freight  service,  on  account  of  the  simple  engine  using  steam 
more  expansively  in  the  former  service  than  in  the  latter.  This 
•is  more  fully  brought  out  elsewhere. 


14  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

in  the  low-pressure  cylinder.  Then,  too,  the  dif- 
ference of  pressure  between  the  two  sides  of  the 
valves  and  pistons  is  less  than  for  simple  engines, 
and  the  wear  should  be  consequently  less. 

On  the  other  hand  many  serious  practical  ob- 
jections have  been  raised.  The  large  cylinders 
greatly  increased  the  weight  of  the  reciprocating 
parts.*  This  must  be  followed  by  heavier  coun- 
ter-balancef  weights  and  their  accompanying 
evils.  %  Also  larger  ports  and  consequently  larger 
valves  must  be  provided  for  the  large  cylinders. 
Inasmuch  as  considerable  difficulty  was  formerly 
experienced  in  obtaining  admission  and  exhaust 
ports  of  sufficient  size  for  the  cylinders  of 
large  high-speed  single-expansion  engines,  it  is 
not  remarkable  that  there  should  have  been  con- 
siderable trouble  experienced  from  this  source  in 
designing  ports  for  the  much  larger  cylinders  of 
the  compound  locomotive. 

In  connection  with  these  last  two  points,  the 
weight  of  reciprocating  parts  and  the  port  re- 


*By  the  reciprocating  parts  is  meant  those  parts  that  have  a 
forward  and  back  (or  reciprocating)  motion.  This  includes  the 
pistons  and  piston-rods,  the  cross-heads  and  a  certain  part  of 
the  main  rods. 

fThe  counter-balance  is  the  balance  weight  placed  in  the 
wheel  at  a  point  opposite  the  crank  pin.  (See  No.  240,  Plate  I.) 

JThe  counter-balance  weights  act  at  all  points  of  the  revolu- 
tion, having  an  outward  or  centrifugal  tendency  from  the  center 
of  the  wheel  that  is  great  at  high  speeds,  and  is  only  counter- 
acted when  the  engine  is  passing  the  front  and  back  centers.  At 
other  points  it  produces  an  upward  tendency  upon  the  engine 
when  moving  up  and  a  downward  blow  upon  the  rails  when 
moving  down. 


COMPOUND  LOCOMOTIVES,  1  5 

quirements,  let  us  see  for  one  moment  what  the 
requirements  for  high  speed  are.  Take  an  engine 
with  a  live  foot  driving  wheel  and  a  twenty-four 
inch  stroke,  traveling  at  the  not  unusual  rate  of 
a  mile  a  minute.  This  requires  386  revolutions 
per  minute,  and  means  that  the  piston  starts  and 
stops  672  times,  and  with  all  its  stopping  and 
starting  travels  1844  feet  per  minute.  At  mid- 
stroke  the  piston  speed  is  about  35  feet  per  second 
or  24  miles  per  hour.  To  the  average  railway 
man  high  speeds  are  so  common  that  I  can  think 
of  no  better  way  to  show  the  full  meaning  of 
these  figures  than  to  compare  them  with  those  of 
a  falling  body  acted  upon  by  gravity.  A  falling 
body  at  the  end  of  the  first  second  is  traveling  at 
the  rate  of  32  feet  per  second,  or  about  22  miles 
per  hour,  and  in  gaining  this  speed  the  body  has 
fallen  some  16  feet,  through  which  distance  the 
continued  action  of  gravity  has  produced  this  not 
inconsiderable  acceleration,  while  in  the  case  of 
the  piston  of  the  locomotive  in  question,  the  still 
greater  speed  of  24  miles  per  hour  must  not  only 
be  attained  by  the  time  the  piston  has  reached 
the  middle  of  its  stroke,  or  in  one  foot,  but  also 
it  must  be  exerting  great  additional  propelling 
power  on  the  crank  pins.  The  steam  in  front  of 
this  rapidly  moving  piston  must  be  exhausted 
freely  or  there  would  be  no  effective  power  to 
maintain  the  speed.  Where  the  reciprocating  parts 
weigh  nearly  a  thousand  pounds,  it  will  be  seen 
what  enormous  power  is  required  to  stop  and 
start  them  without  jar  or  shock  to  the  loco- 
motive, and  also  the  size  of  ports  required  to 


16  EXGIXEEU*'  AX1)  FUIEMEX't  MAXL'AL. 

freely  exhaust  the  pressure  ahead  of  and  freely 
supply  steam  behind  the  very  large  pistons  of 
compound  locomotives.  With  any  of  the  several 
types  of  valve  gear  used  in  locomotive  practice 
to-day,  it  goes  without  saying  that  no  compound 
can  be  relatively  so  efficient,  in  comparison  with 
single-expansion  engines,  in  express  passenger  as 
in  freight  service,  for  the  reasons  hereinbefore 
described.  When  many  single-expansion  loco- 
motives with  moderately  large  ports  require  a  ve- 
locity of  steam  through  their  ports  of  over  1,000 
feet  per  second,  it  can  better  be  imagined  than 
told  what  the  port  requirements  are  for  the  large 
low-pressure  cylinder  on  a  compound.  It  is  gen- 
erally considered  that  for  express  passenger  serv- 
ice the  low-pressure  cylinders  should  not  be  so 
large  in  proportion  to  the  high-pressure  cylinders 
as  for  freight  service. 

Many  of  the  earlier  compounds  in  this  country 
suffered  in  comparative  tests  with  simple  engines 
of  otherwise  similar  design,  by  having  cylinders 
of  too  small  a  size  to  do  the  same  work  as  the 
simple  engine.  While  they  did  their  work  with 
economy,  they  would  not  haul  the  heavy  trains 
of  the  simple  engines,  and  their  supposed  capacity 
had  to  be  reduced,  to  the  annoyance  of  those  en- 
gaged in  the  operating  of  trains.  Since  then,  with 
the  advent  of  larger  cylinders  and  the  "convert- 
ible" class  of  compounds,  the  conditions  have 
become  altered. 

With  any  locomotive,  when  steam  is  shut  off, 
as  in  running  down  grade,  the  pistons  act  as  air 
compressors,  causing  thumping,  rough  riding,  and 


COMPOUND  LOCOMOTI VES.  1 7 

cooling  of  the  cylinders,  as  well  as  a  strong  draft 
in  the  stack  at  a  time  when  no  steam  and  little 
draft  are  required,  and  thus  produce  a  waste  of 
fuel.  The  large  low-pressure  cylinders  of  the 
compound  have  greatly  magnified  this  evil,  and 
several  builders  have  overcome  it  by  the  use  of 
automatic  valves  on  the  low-pressure  cylinder,  by 
which  the  two  sides  of  the  low-pressure  piston  are 
connected  whenever  the  locomotive  is  drifting. 

After  closing  the  throttle,  an  engine  working- 
compound  will  make  several  strokes  before  all 
steam  is  finally  exhausted.  This  delay  in  clear- 
ing the  cylinders  of  steam,  placed  compound 
locomotives  to  considerable  disadvantage  in 
switching  or  like  service;  also,  in  such  service, 
accustomed  to  gauge  the  speed  by  the  exhaust 
of  the  engine,  trainmen  were  often  deceived  by 
the  less  frequent  exhaust  of  the  two-cylinder  com- 
pound. The  employment  of  the  separate  high- 
pressure  exhaust,  whereby  the  engine  can  be  run 
simple  at  the  will  of  the  engineer,  it  appears, 
has  overcome  these  objections  from  an  operating- 
standpoint. 

Many  of  the  earlier  forms  of  intercepting  valves 
were  of  the  poppet  type  and  hammered  badly  in 
opening  or  closing.  It  will  be  noticed  that  these 
valves  in  the  later  designs  are  of  the  piston  type 
and  are  almost  invariably  cushioned  by  dash-pots 
connected  thereto,  or  some  other  equally  effective 
means. 

It  is  also  claimed  that  the  breakage  and  loosen- 
ing of  the  large  low-pressure  cylinders  have  been 
considerably  done  away  with  by  the  use  of  proper 


18  ENGINEER^  AXD  FIREMEN'S  VAXTAL. 

reducing  valves  and  a  better  attachment  of  cylin- 
ders to  the  frame,  the  use  of  double  front  rails  for 
the  latter  being  particularly  noticeable  in  modern 
construction  of  large  locomotives. 

Thus  it  is  that  improvements  in  design  and  con- 
struction are  continually  taking  place,  and  the 
upholders  of  the  great  principle  of  compounding 
will  certainly  witness  their  more  extensive  adapta- 
tion to  all  classes  of  service. 


CHAPTER   III. 

ENGINEERS'  AND    FIREMEN'S    MANUAL  —  CLASSES    OF 
COMPOUND   LOCOMOTIVES  AND   THEIR  GENERAL 

CONSTRUCTION. 

There  are  many  classes  of  compound  locomo- 
tives in  use.  First,  the  strictly  plain  compound, 
where  no  live  steam  is  admitted  to  the  low-pres- 
sure cylinder,  even  in  starting.  The  Webb  three- 
cylinder  compounds  (with  cylinders  arranged  as 
outlined  in  Fig.  106,)  which  are  usually  with- 
out connecting  rods  —  the  two  high-pressure  cylin- 
ders turning  the  rear  pair  of  driving  wheels  by 

two  outside  cranks  while 
the  low-pressure  cylinder 
turns  the  forward  drivers 
by  means  of  an  inside 
crank  —  belong  to  this 
class  and  are  used  in  con- 
siderable numbers  on  the 
London  &  North-Western 
of  England.  They  are  not 
powerful  in  starting,  as 
the  driving  wheels  acted 


upon  by  the  high-pressure  cylinders  must  turn, 
either  by  slipping  or  moving  the  train,  before 
steam  enters  the  low-pressure  cylinder. 

Second,  automatic  compounds  —  those  using  live 
steam  in  the  low-pressure  cylinder  in  starting 
only,  automatically  changing  to  compound  with 
the  first  stroke,  and  thereafter  cannot  be  run  ex- 
cept as  compounds. 


(19) 


20  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

The  third  class  can  be  run  simple  or  compound 
at  any  time  at  the  will  of  the  engineer  and  will 
be  termed  convertible  compounds. 

Each  of  these  principal  classes  may  have  two, 
three,  or  four  cylinders.  The  two-cylinder  or  "cross- 
compound"  always  has  an  intermediate  recepta- 
cle, called  a  receiver,*  between  the  high  and  low- 
pressure  cylinders,  while 
the  four  -  cylinder  en- 
gines may  or  may  not 
have  receivers  —  those 
with  both  pistons  at- 
tached to  the  same 
crosshead  generally 
have  not.  The  three 
systems  of  four-cylinder 
compounds  used  in  this 
country  are  the  Baldwin 
(Vauclain),  the  Brooks 
(Player),  and  the  John- 
stone.  Of  these,  the  Brooks  has  receivers,  while 
the  remaining  two  are  of  the  continuous  expan- 
sionf  type  and  have  no  receivers.  % 

*The  receiver  is  for  the  purpose  of  receiving  the  exhaust  from 
the  high-pressure  cylinder  and  holding  it  until  the  engine  gets 
to  the  point  in  the  revolution  where  it  is  admitted  against  the 
low-pressure  piston.  Incidentally,  the  receiver  may  act  as  a  re- 
heater,  if  located  in  the  smoke-box,  as  is  usually  the  practice. 

fMeaning  expansion  without  any  pause  or  interruption  as  is 
the  case  when  a  receiver  is  interposed  between  the  high  and  the 
low-pressure  cylinders. 

Jin  Europe  the  Hurgarian  State  Railways  employ  four-cylin- 
der tandem  compounds  with  one  receiver  into  which  both 
high-pressure  cylinders  exhaust  and  from  which  both  low-pres- 
sure cylinders  receive  their  supply. 


CLASSES  OF  COMPOUND  LOCOMOTIVES. 


21 


JFiq.103. 


The  arrangement  of  cylinders  is  quite  varied, 
as  shown  by  the  several  skeleton  cuts.  There 
may  be  two  cylinders,  one  high-pressure  and  one 

low-pressure,  as  outlined  in 
Figs.  101,  102  and  103;  one 
high  and  two  low-pressure, 
as  in  Figs.  104  and  105;  two 
high-pressure  and  one  low 
into  which  they  both  ex- 
haust, as  in  Fig.  106;  two 
high,  each  exhausting  in- 
dependently into  a  low- 
pressure  cylinder  on  the 
same  side  of  the  engine, 
shown  in  Figs.  107, 108,  109 
and  110;  or  two  high  ex- 
hausting into  a  common  receiver  from  which 
both  low-pressure  cylinders  draw  their  supply,  as 
in  Figs.  Ill  and  112.  Aside  from  the  varied  ar- 
rangement of  cylinders, 
many  of  the  European 
designs  employ  three 
and  four  cranks  and  use 
no  side  rods.  Some 
French  constructions, 
retaining  the  use  of  side 
rods,  employ  for  the 
high-pressure  cylinders 
two  inside  cranks  on 
one  driving  axle  at  an 
angle  with  the  low- 
pressure  cranks  on  a 
second  driving  axle,  the  angle  between  the  cranks 


22 


ENGINEERS'  AXD  FIUKMKX'S  UAXUAL. 


being  such  as  to  give  as  large  a  turning  power  as 
possible,  for  all  portions  of  the  revolution. 

It  is,  perhaps,  needless  to  say  that  the  wide 
variations  in  the  service 
of  American  locomotives 
demand  that  they  have  a 
large  starting  power  at  all 
points  of  the  stroke.  To 
obtain  this  starting  power, 
all  the  earlier  designs 
used  a  device  called  an  in- 
tercepting valve  that,  if 
closed  in  starting,  cut  off 
communication  between 
the  receiver  and  the  low- 
-pressure  cylinder  and  at 
the  same  time  admitted 
live  steam  to  the  low-pressure  side,  but  after  the 
first  exhaust  from  the 
high-pressure  cylinder  to 
the  receiver  took  place, 
the  pressure  in  the  latter 
automatically  shoved  open 
the  intercepting  valve  and 
simultaneously  shut  off 
the  further  supply  of  live 
steam  to  the  low-pressure 
cylinder.  Hence  these  en- 
gines belong  to  the  auto- 
matic class  of  compounds. 
Mr.  Anatole  Mallet,  who 
was  the  designer  of  the  *"&' ' 

first  practical  compound  locomotives  in  Europe 


GLASSES  OF  COMPOUND  LOCOMOTl  \  'EX. 


in  1876,  was  also  the  first  to  devise  a  means  by 
which  a  compound  could  be  worked  as  a  simple 
locomotive  for  any  desired  period  at  the  will  of 
the  engineer.  This  was  accomplished  by  adding 
a  separate  exhaust  valve  through  which  the  ex- 
haust from  the  high-pressure  cylinder  could  escape 
to  the  atmosphere  without  accumulating  in  the 
receiver.  This  relieved  all  back  pressure  on  the 
high-pressure  piston  and  admitted  of  greater  power 
at  slow  speed  than  was  otherwise  obtained.* 
Many  objections  were  raised  to  placing  the 

operation  of  the  engine 
either  as  a  simple  or  as  a 
compound  in  the  hands 
of  the  engineer,  and  the 
fear  was  freely  expressed 
that  the  average  engineer 
would  run  the  locomotive 
to  its  disadvantage  in 
simple  position  more  than 
enough  to  offset  the  sav- 
ing when  operated  as  a 
compound.  However,  one 
prominent  railroad  officer, 
in  placing  the  operation  of  the  valves  at  the  will 
of  the  engineer,  seemed  to  express  the  now  settled 
conviction  of  all,  when  he  said:  "To  argue  that  an 

*It  should  also  be  stated  that  not  only  were  the  automatic 
compounds  less  powerful,  at  slow  speeds  after  starting,  than 
simple  engines,  but,  except  in  the  case  of  four-cylinder  engines 
having  one  high  and  one  low-pressure  cylinder  on  the  same  side 
they  were  practically  helpless  in  case  of  a  broken  steam  chest 
on  either  side.  The  use  of  the  separate  exhaust  valve  has  greatly 
altered  the  conditions  in  these  cases. 


24  EXGTXEEW  AXJ)  FIREMEX'X  MA3TAL. 

engineer  is  likely  to  work  simple  any  longer  than 
absolutely  necessary,  is  about  the  same  as  saying 
that  an  engineer  with  the  ordinary  engine  cannot 
be  trusted  to  pull  the  reverse  lever  up  as  soon  as 
possible." 

Later  practice  interposed,  within  or  near  the 
intercepting  valve,  a  reducing  valve,  which  is 
used  to  admit  live  steam,  at  a  reduced  pressure 
only,  into  the  low-pressure  cylinder  when  starting 
or  when  working  simple.  This  reduced  the 

abnormal  shocks  that  were 
produced  when  starting- 
large  compounds  of  earlier 
design.  The  reducing 
valve,  the  intercepting 
valve,  and  the  separate 

©/^  \eihaust  valve  were  so 
(-^^v)  closely  combined  in  many 
cases  and  so  dependent, 
one  upon  the  other,  in 
their  operation,  that  it 
'became  the  tendency 


-F-ici.lUo.  .,  , 

T  among  railway  and    me- 

chanical men  to  refer  to  the  wrhole  mechanism 
simply  as  the  "intercepting  valve." 

While  the  limit  to  the  size  of  the  ordinary 
locomotive  may  be  considered  to  have  been 
reached  when  the  largest  practical  boiler  that  can 
be  placed  on  a  given  gauge  track  has  been  attained, 
the  limit  to  the  American  two-cylinder,  or  cross- 
compound,  with  outside  cranks  wall  be  the  max- 
imum width  allowable  for  locomotives.  However, 
again  Mr.  Mallet,  the  father  of  the  present  era 


CLASSES  OF  COMPOUND  LOCOMOTIVES. 


25 


of  compound  locomotives,  has  seemingly  solved 
the  problem  by  dividing  the  low-pressure  cylinder 
into  two  cylinders,  as  shown  in  Fig.  105,  of  smaller 
size  attached  to  the  same  crosshead.  With  such 
a  construction  it  would  appear  that  the  boiler 
would  still  be  the  limiting  feature  of  the  size  of 
the  compound  as  well  as  the  simple  locomotive. 
The  proper  cylinder  ratio  of  compounds  for  all 
varieties  of  service  is  still  somewhat  undeter- 
mined. By  the  cylinder  ratio  is  meant  the  propor- 
tion between  the  volumes  of  the  high  and  the 
low-pressure  cylinders,  not  including  the  clearance 


spaces.  In  American  practice  where  the  length 
of  stroke  is  the  same,  the  cylinder  ratio  would 
be  as  the  areas  of  the  two  pistons,  and  it  can 
readily  be  found  by  multiplying  the  diameter  of 
each  cylinder  by  itself  and  comparing  the  two 
products.  For  instance,  to  find  the  cylinder  ra- 
tio of  an  engine  with  a  20  inch  high  and  a  30 
inch  low-pressure  cylinder,  multiply  20x20  equals 
400;  30x30  equals  900;  400  goes  in  900  two  and 
one-fourth  times,  which  is  the  cylinder  ratio. 


2G 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


The  early  practice  in  this  country  with  two- 
cylinder  compounds  gave  a  ratio  of  two  to  one 
or  even  less,  but  extended  experiment  has  dem- 

onstrated that  a  greater 
proportion  than  this  is 
advisable  and  man  y 
compounds  of  this  class 
have  a  low-pressure  cyl- 
inder from  two  and  one- 
half  to  two  and  three- 
quarters  times  larger 
than  their  high-pressure 
cylinder.  The  Baldwin 
works  used  a  ratio  of  3 
to  1  in  their  Vauclain 


pounds  for  both  passenger  and  freight  service  for 

a  number  of  years  and  consider  the  results  emi- 

nently satisfactory,  while 

the  builders  of  the  Brooks 

tandem  four-cylinder 

compound  advise  a  ratio 

of  between  2.8  and  3  to  1. 

However,  the  whole  prob- 

lem of  cylinder  ratios  for 

compound  locomotives  is 

based  upon  the  desirabil- 

ity of  dividing  the  work 

as  equally  as  possible  be- 

tween   the  high   and  the 

low-pressure  cylinders,  and 

without  going  into  details,  it  is  apparent  that  no 

given  ratio  will  keep  the  work  equally  divided 


00 


CLASSES  OF  COMPOUND  LOCOMOTIVES.  27 

for  different  service  and  different  points  of  cut-off, 
nor  should  this  equal  division  of  power  between 
the  cylinders  be  given  anything  but  secondary 
consideration  in  comparison  with  the  total  econ- 
omy of  the  locomotive.  To  partially  equalize  the 
power  of  compounds,  the  amounts  of  lap  and  lead 
are  not  the  same  for  both  cylinders;  one  builder 
uses  a  separate  lever  in  the  cab  for  independ-' 
ently  adjusting  the  travel  of  the  low-pressure 
valve,  as  fully  described  .elsewhere. 

There  seems  to  be  no  general  rule  followed  by 

builders  in  this  country 
as  to  which  cylinder  of 
a  two-c  y  1  i  n  d  e  r  com- 
pound should  be  placed 
on  the  right-hand  or 
engineer's  side  of  the 
engine.  Generally  the 
intercepting  valves  are 
located  on  the  engi- 
neer's  side  to  make  their 
connections  as  simple  as 
possible,  and  hence,  ac- 
cording  as  the  design 
contemplates  the  plac- 
ing of  this  valve  adjacent  to  the  high  or  the  low- 
pressure  cylinder,  that  one  is  placed  on  the  right- 
hand  side.  But  even  this  rule  is  not  without 
exception.* 

*It,  would  seem  as  though  the  intercepting  valve,  if  placed 
between  the  high-pressure  cylinder  and  the  receiver,  would  cause 
less  wire-drawing  of  steam  to  the  low-pressure  cylinder  than  if 
located  between  the  latter  and  the  receiver. 


28  ENGINEERS'  AND  FIREMEN'*  MANUAL. 

Some  compounds  have  cylinder  casings  both  of 
the  same  size,  but  with  the  advent  of  the  thirty- 
four  or  thirty-five  inch  low-pressure  cylinder  it 
seemed  to  many  advisable  to  place  it  on  the 
engineer's  side  with  the  thought  of  its  better  pro- 
tection from  damage  if  within  his  vision,  and,  fur- 
thermore, that  the  high-pressure  cylinder  casing 
be  made  no  larger  than  necessary  for  reason  of 
its  better  protection  from  accident. 

It  is  becoming  the  general  practice  on  com- 
pounds of  any  size  to  place  combination  safety  and 
relief  valves  on  the  receiver  and  the  low-pressure 
chest  and  cylinder  heads  to  avoid  damage  in  case 
of  broken  reducing  valve  or  other  accident  that 
might  produce  unsafe  pressure  on  that  side. 


CHAPTER   IV. 

ENGINEERS'  AND  FIREMEN'S  MANUAL  —  QUESTIONS 
AND  ANSWERS  ON  THE  OPERATION  OF  COM- 
POUND LOCOMOTIVES  IN  GENERAL. 

In  what  respects  should  the  instructions  for 
firing  compound  locomotives  differ  from  those  for 
single-expansion  engines,  as  described  in  the 
Manual  ?  On  account  of  the  effect  of  the  milder 
exhaust  on  the  fire,  the  fireman  should  carry  the 
fire  as  light  as  possible  and  yet  keep  a  thin  layer 
of  coal  in  a  well  ignited  state  over  the  entire 
surface  of  the  grates. 

Should  the  engineer  observe  any  difference 
between  the  operation  of  a  compound  and  a 
simple  locomotive  ?  Perhaps  the  most  important 
thing  is  that  the  engineer  must  accustom  himself 
to  use  the  reverse  lever  for  what  it  is  intended, 
not  hesitating  to  increase  the  valve  travel  when- 
ever necessary,  and  converting  the  engine  to 
"simple"  only  at  low  speeds  and  after  the  maxi- 
mum power  of  the  engine  working  compound  is 
found  insufficient.  There  will  be  no  such  waste 
of  steam  from  lack  of  expansion  (see  Fig.  100) 
nor  such  serious  injury  to  the  fire  by  working  the 
valves  full  gear  as  is  the  result  with  single-expan- 
sion engines.  Do  not  expect  to  find  the  best  run- 
ning position  of  the  reverse  lever  as  near  the  cen- 
ter of  the  quadrant  as  with  a  simple  engine.  The 
engine  will  do  better  work  with  the  lever  nearer 

(29) 


30  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

full  gear,  just  how  far  depending,  of  course,  on 
the  varying  conditions  of  train,  grade,  and  speed; 
but,  in  general,  do  not  cut  the  lever  back  too  far. 
The  engine  throttle  should  usually  be  run  as 
wide  open  as  possible,  but  judgment  must  be 
used  in  this  respect  according  to  the  existing  cir- 
cumstances. An  engine  designed  for  heavy 
freight  service  may  do  better  under  very  light 
work  or  in  passenger  service,  if  throttled. 

In  order  to  move  and  stop  engines  quickly 
when  desired,  as  for  engine-house  or  turn-table 
work,  how  is  it  advisable  that  compound  engines 
be  handled?  Their  valves  should  be  kept  in 
simple  or  starting  position  whenever  their  con- 
struction will  permit,  in  order  that  the  engines 
may  be  moved  with  the  least  necessary  opening 
of  the  throttle  and  that,  when  the  throttle  is 
closed,  the  pressure  remaining  in  the  pipes  will 
the  sooner  escape. 

In  starting,  why  are  compounds  more  likely  to 
slip  than  other  engines?  If  they  are  started 
working  simple,  their  power  temporarily  is  con- 
siderably greater  than  that  of  simple  engines  of 
the  same  weight,  hence  great  care  should  be 
exercised  by  the  engineer  to  avoid  slipping;  but 
at  any  rate  the  cylinder  cocks  should  be  left  open 
as  long  as  there  is  any  liability  of  water  being  in 
the  cylinders. 

Why  is  it,  that,  under  these  circumstances,  com- 
pound locomotives  frequently  slip  only  a  part  of 
a  turn  instead  of  spinning  around,  as  many 
simple  engines  will  do  unless  steam  is  immedi- 
ately shut  off?  Because,  while  they  are  more 


OPERATION  OF  COMPOUND  LOCOMOTIVES.         31 

powerful  at  slow  piston  speeds,  the  ports  used  for 
starting  are  generally  so  small  that  a  rapid 
movement  of  the  piston  will  so  greatly  reduce 
the  effective  pressure  on  the  piston  as  to  cause 
the  slipping  to  cease,  many  times  without  closing 
the  throttle. 

What  harm  results  from  frequent  slipping  for 
only  a  part  of  a  revolution?  This  will  occur  each 
time  at  that  part  of  the  stroke  where  the  turning 
power  is  the  greatest  and  finally  wear  the  tires 
out  of  round,  so  that  the  wheels  will  pound  badly 
at  high  speeds,  thus  causing  damage  to  the 
machinery  and  track  besides  making  the  engine 
ride  hard. 

Wherein  does  the  lubrication  of  their  cylinders 
differ  from  that  of  simple  engines?  Oil  need 
only  be  supplied  to  the  high-pressure  cylinder  or 
cylinders,  when  the  engine  is  working  compound. 
Hence  a  four-cylinder  compound  would  be  lubri- 
cated, as  usual,  OB  both  sides  of  the  engine,  but 
a  two-cylinder,  or  cross-compound,  would  require 
oil  only  in  the  one  high-pressure  cylinder  when 
working  in  compound  position.  In  this  latter 
class,  valve  oil  should  be  supplied  to  the  low- 
pressure  cylinder,  however,  when  the  engine  is 
starting  or  running  simple,  but  immediately  shut 
off  as  soon  as  the  change  is  made  to  compound 
working. 

What  are  apt  to  be  the  injurious  consequences 
of  feeding  oil  to  the  low-pressure  side  when  the 
engine  is  working  compound  ?  There  being  then 
no  supply  of  live  steam  through  the  reducing  and 
the  intercepting  valves,  the  oil  would  settle  there 


32  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

and  gum  these  valves  so  as  to  cause  them  to 
stick  and,  possibly,  become  inoperative. 

When  is  it  advisable  to  work  the  compound  as 
a  simple  engine?  In  starting  very  heavy  trains, 
and  also  on  heavy  grades  when  it  is  seen  that 
the  power  as  a  compound  with  the  valve  in  full 
gear  is  insufficient. 

When  the  engine  can  be  run  simple  for  any 
period  at  the  will  of  the  engineer,  above  what 
speed  is  it  impracticable  to  do  so?  Above  a 
speed  exceeding  six  or  eight  miles  an  hour. 

What  is  the  reason  for  this?  Because,  as  out- 
lined elsewhere,  the  special  ports  for  use  when 
the  compound  locomotive  is  working  simple  are 
usually  purposely  designed  too  small  to  permit 
of  much  speed. 

If  special  valves  for  use  when  the  engine  is 
drifting  are  not  provided,  what  is  it  advisable  to 
do?  Work  a  little  steam  all  the  time  in  order  to 
keep  the  large  valves  and  pistons  somewhat  lub- 
ricated. 

Why  is  it  more  difficult  to  detect  leaky  valves 
and  cylinder  packing  in  compound  than  in  simple 
engines?  In  the  first  place  it  does  not  so 
seriously  affect  the  good  working  of  the  engine, 
and,  in  the  second  place,  because  the  high-pressure 
cylinder  does  not  exhaust  to  the  atmosphere 
where  a  blow  could  be  heard,  and  also  the 
pressure  behind  the  low-pressure  piston  is  very 
much  lower  than  with  a  simple  engine  and,  con- 
sequently, a  blow  does  not  sound  as  loud. 

What  general  rule  will  apply  to  compound  as 
well  as  simple  locomotives  where  one  side  has  to 


OPERATION  'OF  COMPOUND  LOCOMOTI VES.         33 

be  disconnected  in  cases  of  accident?  On  the 
disabled  side,  always  block  securely  at  both  ends 
of  the  crosshead  and  firmly  secure  the  valve,  under 
all  ordinary  circumstances,  in  the  center  of  its 
seat? 

What  is  usually  the  cut-off  in  the  high-pres- 
sure cylinder  with  the  reverse  lever  hooked  up? 
Some  builders  cut  no  notches  higher  up  in  the 
quadrant  than  would  give  a  cut-off  at  one-half 
stroke,  wrhile  others  notch  the  quadrant  all  the 
way  up  to  the  center. 

Why  is  it  not  necessary  to  have  notches  in  the 
quadrant  for  shorter  cut-off  than  one-half?  A 
shorter  cut-off  than  one-half  for  a  compound  loco- 
motive is  generally  inadvisable  for  reasons  anal- 
agous  to  those  hereinbefore  urged  against  a  shorter 
cut-off  than  one-fourth  for  a  simple  locomotive; 
also  it  prevents  damage  that  might  ensue  from 
excessive  compression.  With  a  ratio  of  2  to  1  be- 
tween the  sizes  of  the  low  and  the  high-pressure  cyl- 
inders, one-half  cut-off  gives  practically  four  ex- 
pansions, a  three-fourths  cut-off  gives  two  and  two- 
thirds  expansions;  with  a  cylinder  ratio  of  3  to 
1,  one-half  cut-off  gives  about  six,  and  three- 
fourths  cut-off  about  four  expansions.  Fig.  100 
clearly  shows,  that,  while  the  most  economical 
cut-off  (as  far  as  the  amount  of  steam  used  is 
concerned)  is  about  one-quarter  of  the  stroke  for 
single-expansion  engines,  it  is  about  one-half 
stroke  for  compounds.  Lighter  work  than  is 
produced  by  full  throttle  and  one-half  cut-off  in 
the  high-pressure  cylinder  can  best  be  obtained 
by  throttling  the  engine. 


34  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

In  what  way  does  the  use  of  a  separate  exhaust 
valve  give  greater  power  to  the  two-cylinder  com- 
pound at  slow  speeds?  Assuming  200  pounds 
boiler  pressure  and  a  cylinder  ratio  of  2i  to 
1,  the  high-pressure  exhaust  reaches  about  57 
pounds  when  the  engine  is  working  compound. 
This  pressure  is  the  receiver  pressure  and  becomes 
the  initial  pressure  (at  slow  speeds)  in  the  low- 
pressure  cylinder.  When  working  simple,  the 
reducing  valve  permits  about  80  pounds  of  live 
steam  to  pass  into  the  low-pressure  cylinder,  thus 
considerably  increasing  the  power  in  that  cylin- 
der. The  high-pressure  piston  also  exerts  an 
equally  increased  power  when  working  simple, 
as  the  back  pressure  of  57  pounds  is  removed  by 
the  separate  exhaust  valve. 

THE  BALDWIN  FOUR-CYLINDER  COMPOUND. 

The  builders  of  the  "Vauclain"  four-cylinder 
compound  locomotives  claim  a  design  productive 
of  the  greatest  efficiency  with  the  utmost  sim- 
plicity of  parts  and  the  least  possible  deviation 
from  existing  practice;  that  they  also  develop 
equal  power  on  each  side  of  the  locomotive, 
thereby  preventing  the  racking  of  the  machinery 
resulting  from  an  unequal  distribution  of  power; 
and  that,  in  their  method  of  handling  by  the 
engineer,  there  is  but  slight  departure  from  that 
of  single-expansion  or  non-compound  locomo- 
tives. They  may  be  started,  and  run  for  any  de- 
sired length  of  time,  either  simple  or  compound, 
at  the  will  of  the  engineer,  and  can  be  changed 
from  the  one  to  the  other  at  his  discretion  by  the 


OP  EH  AT  ION  OF  COMPOUND  LOCOMOTIVES. 


35 


movement  of  a  small  lever  in  the  cab  which  also 
operates  the  cylinder  cocks. 

The  principal  features  of  construction  are  as 
follows: 

The  cylinders  consist  of  one  high-pressure  and 
one  low-pressure  cylinder  for  each  side,  the  ratio 
of  their  volumes  being  as  nearly  3  to  1  as  the 
employment  of  convenient  measurements  will 
allow.  They  are  cast  in  one  piece  with  the  cylin- 
drical valve  chamber  and  the  saddle,  the  cylin- 

fig. 


ders  being  placed  one  directly  above  the  other 
and  as  close  together  as  they  can  be  with  ade- 
quate walls  between  them.  Figs.  113  and  114 
show  the  proximity  of  the  two  cylinders,  while 
in  Fig.  115,  which  shows  the  arrangement  of  the 
cylinders  in  relation  to  the  valve,  the  actual  con- 
struction is  distorted  for  illustrative  purposes. 

The  valve  used  to  distribute  the  steam  to  the 
cylinders  is  of  the  piston  type,  working  in  a  cyl- 
indrical steam  chest  located  in  the  saddle  of 


36  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

the  cylinder  casting  as  close  to  the  cylinders  as 
possible  and  between  them  and  the  smoke-box, 
as  shown  in  the  figures.  This  chest,  having 
steam  passages  cast  larger  than  required,  is 
bored  out  enough  larger  than  the  diameter  of 
the  piston  valve  to  permit  the  use  of  a  hard  cast 
iron  bushing.  Fig.  122  shows  this  bushing  and 
one  method  of  forcing  it  into  place  so  that  steam 
tight  joints  will  be  had  between  all  ports;  it 


also  shows  the  narrow  bridges  across  the  steam 
ports  which  prevent  the  eight  packing  rings  of 
the  valve  (shown  in  Fig.  116)  from  entering  the 
ports.  These  cast  iron  packing  rings  form  the 
edges  of  the  valve. 

The  valve  is  of  the  piston  type — double,  and 
hollow  between  the  two  inside  pistons — but  hav- 
ing two  solid  ends,  as  shown  by  Fig.  116,  and 
controls  the  admission  and  exhaust  of  both  cylin- 
ders. The  exhaust  steam  from  the  high-pressure 


OPERATION  OF  COMPOUND  LOCOMOTIVES,         37 

cylinder  becomes  the  supply  steam  for  the  low- 
pressure  cylinder  and  is  transmitted  from  one 
side  of  the  high-pressure  cylinder  to  the  opposite 

Tiff. 


side  of  the  low-pressure  cylinder  through  the  hol- 
low portion  of  the  valve,  as  indicated  by  arrows, 
Fig.  115.  The  supply  steam  for  the  high-pressure 


38 


ENGINEERS'  AND  FIREMEN'S  MANUAL, 


cylinder  enters  the  steam  chest  at  both  ends, 
thus  balancing  the  valve  with  the  exception  of 
the  area  of  the  valve-stem  at  the  back  end. 

The  more  common  slide  valve  action  being  so 
much  better  understood  by  the  average  railroad 
man  than  the  piston  valve,  I  will  liken  this  four- 
piston  valve  to  one  slide  valve  within  another 
having  external  admission  and  internal  exhaust  in 
both  cases.  Thus  it  will  be  seen  that  the  outside 

'a.  116. 


edges  of  the  two  outer  pistons  govern  admission 
and  their  inside  edges  the  exhaust  of  high-pres- 
sure cylinder,  while  the  two  inner  pistons  simi- 
larly regulate  the  flow  of  steam  to  and  from  the 
low-pressure  cylinder,  all  of  which  will  be  evident 
by  a  reference  to  the  arrows  in  Fig.  115. 

Where  the  front  rails  of  the  frame  are  single 
bars,  the  high-pressure  cylinder  is  usually  put  on 
top,  as  shown  in  Fig.  113,  and  in  that  event,  with 


OPERATION  OF  COMPOUND  LOCOMOTl } 'EH.          39 

the  usual  rocker-arm,  indirect  valve  motion  is 
used.*  When  the  low-pressure  cylinder  is  put 
above  (Fig.  114)  on  account  of  the  double  front 
rails  of  the  frame,  they  also  prevent  the  use  of 
the  rocker-shaft  and  box  and  the  valve  motion  is 
then  termed  direct-acting,  which  necessitates  a 
different  location  of  the  eccentrics  on  the  axle.'* 

Engineers  and  those  employed  in  shops  and 
round-houses  for  setting  valves  and  eccentrics 
should  thoroughly  understand  the  difference  be- 
tween the  position  of  the  eccentrics  with  relation 


€ 


to  the  crank-pins  for  direct  and  indirect  valve 
motion,  as  given  fully  elsewhere  in  the  Manual, 
and  further  brought  out  in  the  Catechism  on 
Accidents  to  Baldwin  Four-Cylinder  Compounds 
hereinafter  contained. 

The  style  of  crosshead  is  shown  in  Fig.  117. 
It  is  made  of  cast  steel,  to  insure  the  greatest 
strength  with  a  minimum  weight,  the  wearing 
surface  being  lined  with  tin.  The  piston,  shown 

*Direct  and  indirect  valve  motion  will  be  found  fully  illus- 
trated and  explained  in  the  earlier  chapters  of  the  Manual. 


40 


ENGINEERS'  AND  FIREMEX\*  M.INUAL. 


in  Fig.  118,  is  also  preferably  made  with  cast 
steel  heads,  the  object  in  both  cases  being  to  re- 
duce the  weight  of  the  reciprocating  parts  to  a 
minimum. 

It  is  obvious,  that,  in  starting  these  locomotives 
from  a  state  of  rest  with  heavy  trains,  it  is  neces- 
sary to  obtain  a  greater  power  than  that  exerted 
by  the  high-pressure  piston  alone,  for  there  would 

Fig.129 


be  no  pressure  on  the  low-pressure  piston  until 
the  high-pressure  cylinder  had  made  one  exhaust; 
hence  it  is  necessary  to  admit  steam  to  the  low- 
pressure  as  well  as  the  high-pressure  cylinders. 
This  is  accomplished  by  the  use  of  the  starting 


OP  EH  AT  ION  OF  COMPOUND  LOGOMOTI VES.         4 1 

valve  (Fig.  119).*  This  is  simply  a  plug-cock 
which  is  opened  by  the  engineer  by  means  of 
suitable  levers  from  the  cab,  to  admit  steam  from 
one  end  of  the  high-pressure  cylinder  to  the  other, 
and  thence,  as  if  it  were  the  ordinary  high-pres- 
sure exhaust,  into  the  low-pressure  cylinder.  This 
same  valve  acts  as  a  cylinder  cock  for  both  ends 
of  the  high-pressure  cylinder  and  is  operated  by 
the  same  lever  that  actuates  the  ordinary  cylin- 
der cocks, which  are  in  this  case  on  the  low-pressure 
cylinder,  thus  making,  probably,  the  most  simple 
starting  device  used  on  any  compound  locomotive 
and  one  not  easily  deranged.  The  operation  of 
the  starting  valve  in  conjunction  with  the  cylin- 
der cocks  is  clearly  shown  in  Fig.  120.  The 
starting  valve  should  be  kept  closed  (position  'N) 
as  much  as  possible,  as  its  indiscriminate  use 
reduces  the  economy  and  makes  the  locomotive 

"logy."t 

Air  valves,  to  prevent  a  vacuum,  are  placed  in 
the  steam  passages  of  the  high-pressure  cylinder, 


*This  is  sometimes  called  the  "By-Pass"  valve,  as  it  connects 
the  two  sides  of  the  high-pressure  piston,  but  for  an  entirely  dif- 
ferent purpose  than  that  to  which  the  by-pass  valves  are  put  in 
connection  with  the  low-pressure  cylinder  as  described  herein- 
after under  the  Richmond  and  the  Rogers  compound,  and  for  that 
reason  I  have  not  called  it  a  "by-pass"  valve.  Two  earlier 
forms  of  starting  valves  have  been  used  with  Vauclain  com- 
pounds, but,  inasmuch  as  they  have  been  superseded  by  this  form 
of  valve,  it  is  not  deemed  necessary  to  illustrate  and  describe 
them  herein. 

fAn  engine  which  should  be  capable  of  high  speed  but  is  not, 
and  in  which  the  pressures  work  against  themselves  in  the  cyl- 
inders, is  said  to  be  "logy." 


42  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

a  practice  now  generally  followed  on  all  locomo- 
tives, either  simple  or  compound.  Additional  air 
valves,  marked  C  and  6T|  in  Fig.  120,  are  placed 
in  connection  with  the  ports  in  the  valve  cham- 
ber leading  to  the  low-pressure  cylinders.  Air 
valves  of  somewhat  different  shape  have  been 
described  and  shown  in  detail  heretofore  in  the 
Manual. 

Water  relief  valves  W  W,  Figs.  120  and  121, 
which  are  nothing  more  nor  less  than  pop  valves, 
are  applied  to  the  low-pressure  cylinders  and  at- 
tached to  the  front  and  back  cylinder  heads  to  re- 
lieve excessive  pressure  of  any  kind,  steam  or 
water.  The  spring  in  the  water  relief  valves  on 
these  engines  is  made  to  carry  a  pressure  enough 
greater  than  the  boiler  pressure  to  prevent  their 
discharging  steam  and  water  ordinarily  in  start- 
ing the  engine  simple. 

In  all  other  respects  the  locomotive  is  the  same 
as  the  ordinary  single  expansion  locomotive. 

Operation  of  the  Baldwin  Four-Cylinder  Com- 
pound.— When  starting  the  locomotive,  the  engi- 
neer should,  ordinarily,  pull  the  cylinder  cock 
lever  way  back  and  thus  open  the  cylinder  cocks 
in  order  to  relieve  the  cylinders  of  condensation, 
and,  as  the  starting  valve  is  opened  by  the  same 
movement,  steam  is  thus  admitted  to  the  low- 
pressure  cylinder  and  the  locomotive  started 
quickly  and  freely. 

In  case  the  locomotive  is  at  a  platform  of  a 
crowded  station,  or  in  any  other  place  where  it  is 


OPERATION  OF  COMPOUND  LOCOMOTI VES. 


43 


undesirable  to  open  the  cylinder  cocks,  the  en- 
gineer should  move  the  starting  lever  in  the 
opposite  direction  from  that  usually  given  it, 

JigJZO. 


placing  the  starting  valve  handle  in  position  J, 
Figs.  119  and  120;  that  is,  heshould  pushforward 
the  lever  in  the  cab,  thus  allowing  steam  to  pass 


44 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


through  the  starting  valve  without  opening  either 
the  low-pressure  cylinder  cocks  or  the  drip  C  of 
the  starting  valves.  By  further  reference  to  Fig. 
119,  it  will  be  seen  how,  when  the  handle  is  in  po- 
sition K,  ports  A,  B,  and  drip  C  are  all  connected 
by  the  ports  a,  b,  and  c  of  the  plug;  but  if  the  handle 
is  in  the  opposite  position  J,  ports  A  and  B  only 
are  connected,  as  b  is  .now  at  a  and  c  is  opposite 
B',  in  its  central  position  N  (normal  position  for 
compound  working),  it  will  be  seen  that  all  ports 
are  closed  as  in  the  figure. 

Tig.  J  21. 


rrtn  JZur-Cg/exafc 


After  a  few  revolutions  have  been  made  and 
the  cylinders  are  free  from  water  caused  by  con- 
densation or  priming,  the  engineer  should  move 
the  cylinder  cock  lever  into  the  central  position,  N, 
causing  the  engine  to  work  compound  entirely. 
This  should  be  done  before  the  reverse  lever  is 
disturbed  from  its  full  gear  position. 

Ordinarily,  the  reverse  lever  should  not  be 
"hooked  up,"  thereby  shortening  the  travel  of 


OPERATION  OF  COMPOUND  LOCOMOTI VES.         45 

the  valve,  until  after  the  cylinder  cock  lever  has 
been  placed  in  its  central  position,  but  it  is  often 
necessary  to  open  the  cylinder  cocks  when  at 
full  speed  to  allow  water  caused  by  priming  or 
foaming  to  escape  from  the  cylinders,  and  in  such 
cases  no  disadvantage  is  experienced,  and  the 
reverse  lever  need  not  be  disturbed. 

The  starting  device  is  simply  designed  for 
use  in  the  starting  of  the  train  and  should  not  be 
used  at  any  other  time  unless  there  is  imminent 
danger  of  stalling  and  the  lever  has  been  previ- 
ously dropped  to  full  gear.  In  other  respects, 


aside  from  these  here  noted,  the  rules  governing 
the  operation  of  compound  locomotives  in  gen- 
eral should  be  clearly  understood  by  any  engineer 
who  is  liable  to  be  called  upon  to  run  a  compound 
locomotive  of  this  or  other  design. 

REPAIRS. 

The   builders   of    the   Vauclain   four-cylinder 
compound   claim   an    advantage  in   it  over  the 


46  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

two-cylinder  or  "  cross-compound  "  locomotive 
in  simplicity  of  parts,  there  being  no  intercept- 
ing valve,*  and  a  similarity  to  all  the  parts  of  a 
single-expansion  locomotive.  Thus  its  repairs 
will  be  similar  to  those  of  simple  locomotives. 
To  carry  out  this  simplicity  of  parts,  the  piston 
rods  of  the  high  and  low-pressure  cylinders  are 
of  the  same  diameter  and  designed  strong  enough 
to  withstand  the  severest  strains  of  service. 

The  packing  rings  in  the  valves  are  easily 
replaced  and  the  valve  chest  bushing  can  be 
cheaply  and  easily  renewed.  In  extracting  old 
bushings  it  is  best  to  split  them  between  the 
ports  with  a  narrow  chisel.  The  new  bushings 
can  be  pressed  in  by  some  such  handy  device  as 
that  shown  in  Fig.  122. 

Accidents  to  Ba Idwin  Four- Cylinder  (  " Vauclain"  ) 
Compounds. — For  all  ordinary  accidents,  such  as 
broken  main  rod  or  pin,  or  a  broken  valve  stem, 
what  should  be  done?  The  same  as  for  non- 
compound  or  simple  locomotives,  as  described 
fully  in  the  earlier  chapters  of  the  Manual. 

With  a  low-pressure  cylinder  head  knocked 
out,  would  it  be  necessary  to  disconnect  that 
side  ?  Not  for  a  short  distance. 

In  that  event,  how  many  exhausts  would  there 
be  during  one  revolution  ?  There  would  be  three 


*The  intercepting  valve  is  the  valve  which  prevents  the  live 
steam  which  is  admitted  from  the  boiler  to  the  low-pressure  cyl- 
inder at  certain  times,  from  passing  through  the  receiver  to  the 
high-pressure  cylinder  where  it  would  produce  back  pressure  on 
the  piston. 


OPERATION  OF  COMPOUND  LOCOMOTI  VEti.         47 

in  the  stack  and  one  through  the  open  cylinder 
head  and  the  latter  exhaust  might  obstruct  the 
engineer's  view,  if  on  his  side,  and  render  the 
procedure  inadvisable. 

With  the  Vauclain  Compound,  at  what  posi- 
tion of  the  reverse  lever  is  work  of  the  two 
cylinders  most  nearly  equalized  ?  At  a  cut-off 
of  about  one-half  the  stroke  in  the  high-pressure 
cylinder. 

When  is  the  work  most  unequal  and  the 
strains  on  the  crosshead  consequently  the  great- 
est ?  In  starting  with  the  engine  working  sim- 
ple, as  then  the  high-pressure  piston  is  nearly 
balanced  by  live  steam  on  both  sides  and  the 
low-pressure  cylinder  obtains  approximately  boiler 
pressure. 

What  results  would  be  likely  should  the  rig- 
ging of  the  cylinder  cocks  and  starting  valve 
become  bent  or  disconnected  ?  Should  one  start- 
ing valve  fail  to  properly  close,  the  exhausts 
would  be  of  unequal  intensity.  If  one  of  them 
failed  to  open  when  required  in  starting,  the 
engine  would  be  weak  on  that  side  as  it  would 
have  to  start  compound,  that  is  with  steam  for  the 
first  stroke  in  the  small  high-pressure  cylinder 
only. 

In  this  latter  event,  when  would  the  first 
exhaust  from  that  side  take  place  ?  Not  until 
the  completion  of  the  return  stroke. 

If  the  cylinder  cocks  open  and  close  with  the 
same  rigging  as  the  by-pass  valve,  why  would  not 
the  engineer  know  thereby  that  the  by-pass  valve 
was  in  position  desired  ?  From  the  previous 


48  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

description  of  this  rigging,  shown  in  Figs.  119 
and  120,  it  should  be  remembered  that  the  cab 
lever  pushed  clear  ahead  opens  the  by-pass  valve, 
but  not  its  drip  nor  the  cylinder  cocks. 

Before  altering  the  valve  motion,  what  else 
should  be  examined  if  the  exhausts  were  of  un- 
equal intensity  ?  Examine  for  broken  packing 
rings  in  the  piston  valve  or  the  low-pressure 
cylinder.* 

Jn  case  a  valve-stem  broke  off  inside  the  chest 
or  the  valve  itself  broke,  would  it  be  certain  of 
discovery  at  once,  as  with  an  ordinary  slide  valve  ? 
Possibly  it  would  not.  Instances  have  been  cited 
where  compound  locomotives  of  this  system  have 
hauled  passenger  trains  long  distances  with  bro- 
ken valve-stems  and  broken  valves.  The  two 
ends  of  the  valve  being  unbalanced  by  the  area 
of  the  valve-stem  (see  Figs.  115  and  116)  accounts 
for  the  first  possibility,  while  live  steam  from  the 
induction  ports  acting  on  ea,ch  end  of  the  valve 
would  explain  the  case  of  an  undetected  broken 
valve. 

How  can  it  be  found  if  the  cylinder  packing 
in  the  high-pressure  cylinder  is  blowing?  Put 
the  engine  on  the  quarter,  block  the  wheels,  and 
test  as  usual  for  leaky  slide  valve;  then,  with  the 
starting  valve  closed  (in  compound  position)  and 
the  low-pressure  cylinder  cocks  blocked  open, 

*A  case  is  cited  by  the  builders  where  an  engineer  ran  his 
locomotive  two  days  without  any  piston  head  at  all  in  one  of  the 
high-pressure  cylinders,"  and  even  then  could  not  tell  what  was 
the  matter  except  that  the  intensity  of  the  exhausts  were  unequal 
and  the  engine  did  not  make  good  time.  Machinists  put  to  work 
to  locate  the  trouble,  found  it  to  the  great  surprise  of  the  engineer. 


OPERATION  OF  COMPOUND  LOCOMOTIVES. 


49 


drop  the  reverse  lever  into  full  gear.  Steam 
passing  the  high-pressure  piston  will  appear  at 
the  open  cylinder  cock  of  the  low-pressure  cyl- 
inder, but  at  the  opposite  end  that  would  be 
expected  with  a  simple  engine. 

How  can  it  be  found  if  the  packing  in  the  low- 
pressure  cylinder  is  blowing  ?  Put  the  engine 
on  the  quarter  and  open  the  starting  valve  and 
cylinder  cocks  and  look  for  any  escape  of  steam 
from  the  low-pressure  cylinder  cock  on  the  end 
that  should  be  in  exhaust,  as  with  a  simple  engine. 


.  /23. 


With  the  four-cylinder  type,  where  the  large 
low-pressure  cylinder  is  placed  on  top,  as  in  Fig. 
114,  and  direct  valve  motion  is  employed,  how 
should  the  eccentric  rods  on  one  side  stand  with 
the  same  side  of  the  engine  on  the  forward  cen- 
ter ?  They  should  be  crossed,  as  shown  in  skel- 
eton Fig.  123.  A  slipped  eccentric  should  be 
set  the  same  as  for  similar  valve  motion  on  a 
simple  engine,  as  fully  described  heretofore  in  the 
Manual  under  "Third  Examination  of  Firemen." 


50 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


THE    BALDWIN    TWO-CYLINDER    COMPOUND. 

The  original  Baldwin  two-cylinder  compound, 
built  in  the  year  1892,  was  of  the  cross-compound 
receiver  type  and,  after  the  first  stroke  or  twro, 


or  as  soon  as  the  receiver  had  attained  a  pressure 
of  100  Ibs.,  the  engine  automatically  changed  to 
compound  and  could  not  be  operated  otherwise. 
It  belonged,  therefore,  to  the  automatic  class  of 
compounds.  The  reducing  and  the  starting  valve 


OPERATION  OF  COMP  OUND  L  OC  OMOTI VES.         5 1 

then  employed  were  changed  materially  in  the 
later  design  of  the  two-cylinder  compound  here- 
with illustrated  and  described. 

Their  later  two-cylinder  compound  locomo- 
tives belong  to  the  class  of  convertible  com- 
pounds, as  they  can  be  operated  either  simple  or 
compound  for  any  length  of  time  by  the  move- 
ment of  a  small  valve  in  the  cab,  as  shown  by 
Fig.  128. 

Fig.  124  shows  a  front  view,  giving  the  gen- 
eral arrangement  of  cylinders,  steam,  exhaust  and 
receiver  pipes  in  the  front  end,  and  the  location 
of  the  intercepting  and  reducing  valve  in  the 
saddle  of  the  high-pressure  cylinder.  The  low- 
pressure  cylinder  derives  all  its  pressure  from  the 
receiver  when  running  compound,  as  is  usual  in 
two-cylinder  compounds. 

The  office  of  the  intercepting  valve  is  two-fold. 
It  acts  as  an  intercepting  valve  by  opening  and 
closing  communication  between  the  two  cylin- 
ders, and  also  as  a  separate  exhaust  valve,  by  con- 
necting the  low-pressure  cylinder  with  the  exhaust 
to  the  stack.  This  it  does  by  diverting  the  ex- 
haust from  the  high-pressure  cylinder  either  into 
the  atmosphere,  when  working  single-expansion, 
or  into  the  receiver,  when  working  compound, 
and  is  operated  at  the  will  of  the  engineer. 

The  office  of  the  reducing  valve  is  to  admit 
live  steam  at  a  reduced  pressure  into  the  receiver 
and  thence  to  the  low-pressure  cylinder,  when 
the  engine  is  working  single-expansion,  and  also 
to  close  simultaneously  with  the  changing  of  the 
intercepting  valve  to  the  position  which  causes 


52 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


the  engine  to  work  compound,  so  that  the  receiver 
will  obtain  no  live  steam  from  boiler  when  taking 
the  exhaust  from  high-pressure  cylinder.  The 
performance  of  the  first  above-mentioned  func- 
tion— that  of  reducing  the  pressure  of  live  steam 
delivered  to  the  receiver — is  necessary  in  order 


that  the  total  pressure  on  the  large  low-pressure 
piston  shall  not  be  greater  than  that  on  the  high- 
pressure  piston,  and  thus  the  low-pressure  side 
kept  from  jerking  the  train  and  producing  unequal 
strains  on  the  two  sides  of  the  locomotive  when 
working  as  a  simple  engine. 


OPERATION  OF  COMPOUND  LOCOMOTI  VEX.         53 

Operation  of  the  intercepting  and  reduction 
valves. — In  Figs.  125  and  126  the  intercepting 
valve  is  marked  A  and  the  reducing  valve  C. 
It  will  be  seen  that  they  are  both  cylindrical  in 


~Pipelo  Operattnlj 
ledve  in  Cab 


form,  are  placed  in  bushings  having  suitable  ports, 
and  that  coil  springs  hold  them  in  their  normal 
positions  when  no  pressure  is  acting  against  them 
to  overcome  these  springs. 


54  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

In  the  cab  of  the  locomotive  is  placed  an  oper- 
ating valve,  shown  in  Figs.  127  and  128,  having 
two  positions,  marked  "SIMPLE"  and  "COMPOUND." 
Through  this  operating  valve  a  pressure  of  air  or 
live  steam  is  admitted  to  one  side  of  the  reducing 
and  the  intercepting  valves  through  two  pipes 
marked  DD,  and,  acting  against  the  right  end  of 
valve  A  and  against  the  left  end  of  valve  C,  moves 
both  from  their  normal  positions  shown  in  Fig. 
125  to  those  of  Fig  126. 

The  reducing  valve  C,  when  it  is  not  closed 
permanently  by  live  steam  from  the  operating 
pipe  D,  is  automatically  closed  when  the  pressure 
in  the  receiver  R  is  great  enough  to  produce  as 
much  power  in  the  large  low-pressure  cylinder  as 
is  obtained  in  the  smaller  high-pressure  cylinder. 
For  this  purpose  steam  from  the  receiver  E  can 
pass  through  a  port  E,  raising  the  poppet  valve  F 
(which  remains  open  as  long  as  the  engine  is  not 
working  compound)  and  bears  upon  the  larger 
end  of  the  reducing  valve  C,  causing  it  to  move  to 
the  right  and  close  the  live  steam  passage  H 
(shown  in  Fig.  125)  leading  to  the  receiver  E, 
whenever  the  receiver  pressure  becomes  excessive. 
Thus  it  will  be  seen  that  when  the  engine  is  work- 
ing simple  there  must  be  a  close  balance  between 
the  left-hand  larger  end  of  the  reducing  valve, 
being  acted  upon  by  receiver  pressure,  and  the 
right-hand  smaller  end  of  the  reducing  valve, 
being  acted  upon  by  live  steam  from  the  main 
steam  pipe  S.  In  this  way  is  the  receiver  pressure 
kept  as  much  lower  than  the  boiler  pressure  as 
the  large  end  of  the  reducing  valve  is  greater  than 


OPERATION  OF  COMPOUND  LOCOMOTIVES, 


55 


the  small  end.  This  proportion  is  relative  to  the 
respective  sizes  of  the  high  and  the  low-pressure 
cylinders  and  hence  equal  cylinder  power  will  be 
given  both  sides  of  the  engine  in  working  simple. 
When  the  engine  is  standing,  the  lever  of  the 
small  operating  valve,  Figs.  127  and  128,  in  the 
cab  should  be  placed  at  position  marked  "SIMPLE," 
and  the  valves  are  then  in  position  for  the  engine 
to  work  as  a  single-expansion  locomotive,  as  the 

steam  pressure  is  relieved 
through  this  cab  valve  from 
the  large  end  of  the  reducing 
valve  and  the  right-hand  end 
of  the  intercepting  valve,  al- 
lowing these  valves  to  as- 
sume (by  the  action  of  their 
springs) their  respective  posi- 
itions  shown  in  Fig.  125.  The 
arrows  in  this  figure  illus- 
trate clearly  how  the  steam 
can  pass  from  the  high-pres- 
sure exhaust  through  the 
intercepting  valve  A  to  the 
independent  exhaust  B  lead- 
ing to  the  stack  (see  dotted  lines  and  arrows).  At 
the  same  time  the  passage  of  live  steam  to  the  re- 
ceiver— from  which  the  low-pressure  cylinder 
receives  its  supply — takes  place  through  ports  H, 
as  shown  by  other  arrows.  The  receiver  pressure 
is  governed  by  the  automatic  action  of  the  reduc- 
ing valve,  as  previously  explained. 

Thus  the  engine  can  be  used  as  a  single-expan- 
sion locomotive  in  making  up  and  starting  trains, 


Ob  ENGINEERS'  AND  FIREMEN'S  MANTTAL. 

and  then,  at  the  will  of  the  engineer,  the  operat- 
ing valve,  Figs.  127  and  128,  in  the  cab  can  be 
moved  to  the  position  marked  "COMPOUND."  This 
will  admit  live  steam  through  the  two  supply 
pipes  D,  thence  to  the  cylinders  marked  Wand 
C1,  Fig.  126,  changing  the  intercepting  and  the 
reducing  valves  quickly,  and,  as  the  ports  are 
small,  noiselessly,  to  the  position  shown  in  the 
latter  figure.  With  the  intercepting  valve  in  this 
position  it  will  be  seen  that  the  independent  ex- 
haust B  is  closed  and  steam  from  the  high-pressure 
exhaust  must  follow  the  course  of  the  arrows  to 
the  receiver,  passing  around  the  small  reduc- 
ing valve  bushing  and  its  valve  C  which  is  kept 
closed  by  the  live  steam  from  pipe  D. 

At  any  time  the  engineer  may  desire  to  in- 
crease the  power  of  the  engine  as,  for  instance, 
when  in  danger  of  stalling,  by  moving  the  lever 
of  the  operating  valve  in  the  cab  to  position 
marked  "SIMPLE "the  engine  is  again  changed 
at  once  to  a  single-expansion  locomotive. 

Accidents  to  Baldwin  Two-Cylinder  Compounds. 
—With  one  side  disabled,  what  should  be  done  in 
order  to  safely  run  the  engine  in  ?  Disconnect 
the  disabled  side,  as  advised  for  simple  engines, 
place  the  intercepting  valve  in  position  for  work- 
ing simple  so  as  to  open  the  separate  exhaust 
port,  and  run  in  with  one  side. 

Should  the  small  pipes  DD  leading  to  the  reduc- 
ing valve  C  and  the  intercepting  valve  piston  be 
broken  off,  how  could  the  engine  be  worked  ? 
With  single-expansion  only,  unless  the  back  head 
of  the  separate  exhaust  chamber  TFwere  removed 


OPERATION  OF  COMPOUND  LOCOMOTI VES.         57 

and  the  piston  blocked  in  the  position  shown  in 
Fig.  126;  then  the  engine  would  become  an  auto- 
matic compound,  that  is,  would  start  simple  but 
automatically  go  to  compound  after  a  revolution 
or  so. 

What  would  it  be  advisable  to  do  in  case  of  a 
broken  reducing  valve  ?  Use  very  light  throttle  at 
slow  speeds,  or  run  with  a  reduced  boiler  pressure. 

Should  the  small  valves  F  and  G  be  frequently 
inspected  and  cleaned?  Yes.  These  valves  and  the 
reducing  and  the  intercepting  calves  become 
gummed  by  the  injudicious  use  of  cylinder  oil  on 
the  low-pressure  side. 

THE    SCHENECTADY    COMPOUND. 

Locomotives  built  by  the  Schenectady  Loco- 
motive Works  are  oftentimes  styled  by  the  older 
railway  men  as  "  McQueen"  engines,  although 
the  name  of  the  builders  has  been  as  at  present 
for  many  years. 

These  builders  have  constructed  many  com- 
pound locomotives,  and,  including  the  original 
valve  design,  have  employed  three  styles  of  com- 
pound mechanisms,  but  all  engines  built  have 
been  of  the  two-cylinder  variety  of  compounds. 

Original  Schenectady  Type. — The  original  design 
by  their  then  superintendent,  Mr.  A.  J.  Pitkin, 
consisted  of  an  intercepting  valve  and  a  reducing 
valve.  The  stem  of  the  intercepting  valve  was 
connected  by  levers  to  an  index  in  the  cab,  which 
showed  its  position  to  the  engineer.  These  engines 
belonged  to  the  class  of  automatic  compounds. 


58  ENGINEERS'  ANU  FIREMEN'S  MANUAL. 

In  starting  the  engine,  a  small  pipe  from  the 
boiler  through  a  reducing  valve  supplied  steam 
to  the  low-pressure  cylinder  at  a  reduced  pressure. 
When  the  receiver  had  accumulated  sufficient 
pressure  by  the  exhaust  into  it  from  the  high- 
pressure  cylinder,  the  intercepting  valve  would 
automatically  be  thrown  to  its  normal  position 
for  working  compound;  then  the  supply  of  live 
steam  to  the  low-pressure  cylinder  was  cut  off 
and  the  receiver  pressure  admitted,  and  thus  the 
engine  worked  compound. 

The  following  modification  of  this  valve  ar- 
rangement was  afterwards  made  by  Mr.  Pitkin 
and  applied  to  many  locomotives  by  the  Schenec- 
tady  Locomotive  Works. 

Design  of  1892. — With  this  construction  of 
1892,  the  opening  of  the  throttle  admits  live 
steam  at  the  same  time  to  both  the  high  and 
the  low-pressure  cylinders,  closes  the  intercepting 
valve  and  allows  the  engine  to  start  with  its 
full  power  as  a  simple  engine.  After  a  few 
strokes  the  receiver  pressure  automatically  opens 
the  intercepting  valve  and  cuts  off  the  passage 
of  live  steam  to  the  low-pressure  cylinder  and 
the  engine  works  compound.  The  special  valves 
are  located  in  and  behind  the  saddle  on  the  low- 
pressure  side  and  are  operated  automatically  and 
beyond  the  will  of  the  engineer.  Fig.  129  shows 
the  general  appearance  of  that  portion  of  the 
intercepting  valve  projecting  back  of  the  saddle; 
Figs.  130  and  131  show  the  valves  and  pistons 
removed  from  their  encasing  chambers.  Upon 
opening  the  throttle,  a  small  connection  from  the 


OPERATION  OF  COMPOUND  LOCOMOTIVES. 


59 


steam  pipe  admits  live  steam  through  suitable 
valves  to  an  actuating  piston,  the  movement  of 
which  opens  a  poppet  valve,  supplying  live 
steam  to  the  low-pressure  cylinder,  and  also  places 
the  intercepting  valve  so  as  to  close  connection 
between  the  receiver  and  the  low-pressure  steam 

THE  INTERCEPTING  VALVE. 

1892 


chest.  Thus  the  low-pressure  cylinder  exhausts 
to  the  atmosphere  and  the  high-pressure  cylinder 
into  a  closed  receiver.  Sufficient  pressure  will 
accumulate  in  the  receiver  after  a  few  strokes  to 
move  the  small  valves,  thereby  moving  the  actua- 
ting piston  and  with  it  the  intercepting  valve,  to 


60 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


such  position  as  will  close  off  live  steam  to  the 
low-pressure  cylinder,  and  instead  admit  the 
receiver  pressure,  thus  working  the  engine  com- 
pound. 

For  the  benefit  of  those  interested  in  the  de- 
tails of  this  device,  a  more  thorough  description 
of  the  accompanying  figures  follows: 


The  front  view,  Fig.  132,  shows  the  general 
arrangement  of  cylinders,  steam  passages,  and 
the  intercepting  valve.  Figs.  133  and  134  both 


OPERATION  OF  COMPOUND  LOCOMOTI VES.          6 1 

show  the  same  horizontal  section  through  the 
saddles  and  show  the  intercepting  valve  and  the 
actuating  valves,  Fig.  133  showing  them  in  posi- 
tion for  working  compound,  and  Fig.  134  for 
starting.  Fig.  135  gives  a  vertical  section,  better 
showing  the  passages  between  the  receiver  and 
the  low-pressure  steam  chest,  which  passages  are 
opened  and  closed  by  the  double  pistons  GG 
which  form  the  intercepting  valve.  Of  the  remain- 
ing figures,  136  and  137  show  details  of  the  regu- 
lating valve,  and  Fig.  138  an  end  view  of  the 
intercepting  pistons  GG.  The  arrows  in  Figs. 
133  and  134  indicate  the  direction  of  the  steam 
in  passing  through  the  apparatus. 

Fig.  132  shows  a  smoke-box  mounted  on  sad- 
dles connected  with  the  high  and  low-pressure 
cylinders  located  on  opposite  sides  of  the  engine 
and  having  the  necessary  admission  and  exhaust 
ports.  The  exhaust  port  of  the  high-pressure 
cylinder  is  connected  by  a  passage  E  (see  dotted 
lines  in  Fig.  132  and  full  section  of  port  in  Figs. 
133  and  134)  with  the  receiver  at  R,  Fig.  132. 
The  other  end  of  the  receiver  connects  with  the 
inlet  passage  R1  (shown  also  in  Fig.  135)  leading 
to  the  lowT-pressure  steam  chest,  and  in  this 
passage  the  intercepting  valve  GG  is  located  and 
travels  across  it  to  open  or  close  this  passage. 

The  intercepting  valve  and  the  mechanism  for 
operating  it  are  mounted  on  the  saddle  of  low- 
pressure  cylinder,  as  before  stated,  while  the  live 
steam  pipe  S  and  the  high-pressure  exhaust  pas- 
sage E  are  situated  in  the  high-pressure  saddle. 
The  low-pressure  exhaust  passage  E1  is  formed 


62 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


by  the  two  saddles  being  bolted  together,   see 
Figs.  133  and  134. 

The  intercepting  valve  consists  of  two  pistons 
GG  (having  several  small  holes  y  through  them 
in  order  to  balance  them,  see  Figs.  135  and  138) 
mounted  at  one  end  of  a  long  piston  rod,  which 


moves  to  and  fro  in  a  cylinder  having  four  open- 
ings. The  two  large  openings  shown  lead  from 
the  receiver  to  the  low-pressure  steam  chest  (see 
Fig.  135)  and  are  closed  by  the  two  intercepting 
pistons  GG  when  the  engine  is  to  be  started,  so 
that  live  steam  mav  be  admitted  to  the  low- 


OPERATION  OF  COMPOUND  LOCOMOTIVES, 


63 


pressure  cylinder  without  producing  a  back 
pressure  in  the  high-pressure  cylinder  through 
the  receiver.  Of  the  two  remaining  openings  in 
the  valve  cylinder,  port  D  leads  to  the  low-pressure 
steam  chest  and  port  F  admits  steam  from  the 
boiler  when  the  apparatus  stands  in  position  as 
shown  in  Fig.  134. 


The  back  end  of  the  intercepting  piston-rod 
passes  through  suitable  stuffing  boxes  to  a  small 
cylinder  provided  with  a  piston  H,  which  actuates 
the  intercepting  valve.  This  cylinder  has  a  small 
steam  chest,  slide  valve  and  admission  and  exhaust 


64 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


ports  so  similar  to  those  of  an  ordinary  locomo- 
tive cylinder,  that  its  operation  will  be  made  plain 
by  referring  to  the  Figs.  133  and  134,  if  the  move- 
ments of  its  slide  valve  are  explained.  This 


LJ-T 

small  slide  valve,  Fig.  131,  is  moved  by  a  stem 
connecting  two  pistons,  K  and  Kl,  of  unequal 
diameter  in  order  to  insure  their  movement  in 
the  proper  direction  at  the  proper  time.  The 
actuation  of  these  pistons,  and  with  them  the  slide 


OPERATION  OF  COMPOUND  LOCOMOTIVES. 


65 


valve,  will  be  made  clear  by  the  figures.  From 
Fig.  135  it  will  be  seen  that  a  small  pipe  R~  leads 
from  the  receiver  connection  Rl  to  this  valve 
mechanism,  and  from  Figs.  133  and  134,  that  a 
pipe  Sl  comes  from  the  live  steam  passage  in  the 
saddle  and  has  a  small  port  leading  to  the  actu- 
ating valves  as  well  as  to  the  poppet  valve  N. 
These  live  steam  and  receiver  connections  come 
to  opposite  sides  of  a  small  piston  valve  M  (Fig. 
137),  which  is  called  the  "regulating  valve"  and 
travels  across  two  ports  leading  to  the  slide  valve 
beneath  it,  as  shown. 


The  remainder  of  this  mechanism  consists  of  a 
balanced  poppet  valve  N,  which,  when  open,  ad- 
mits live  steam  from  pipe  $l  through  the  inter- 
cepting valve  to  the  low-pressure  cylinder  in 
starting.  This  poppet  valve^has  a  projecting 
stem  on  the  lower  side  and  is  opened  and  allowed 
to  close  by  a  rocker-arm  or  bell-crank  L,  its 
two  positions  being  shown  in  Figs.  133  and  134, 
respectively. 

The  operation  of  the  apparatus  is  as  follows: 
The  normal  position  of  the  parts  when  the  en- 
gine is  working  compound  is  shown  in  Fig.  133, 
in  which  position  steam  for  the  low-pressure 


66  WKGlNEE'lt8\  ANT)  FTREMEX'x  M.  \XUAL. 


cylinder  comes  entirely  from  the  high-pressure 
exhaust  through  the  receiver.  To  start  the  train, 
the  engine  throttle  is  opened  as  usual.  This  per- 
mits steam  to  pass  to  the  high-pressure  side  and 
also  through  the  pipe  $l  (Figs.  133  and  136)  to 
the  left  side  of  piston  valve  M  (Fig.  137)  and 
down  through  the  adjacent  port  (as  indicated 
by  arrows)  to  the  slide  valve  chamber,  there  act- 
ing between  the  two  pistons  K  and  Kl  (Figs. 
131,  133  and  137).  The  right-hand  piston,  being 
the  larger,  causes  a  movement  of  the  slide  valve 
from  its  position  shown  in  Fig.  133  to  that  shown 
in  Fig.  134,  thereby  uncovering  the  steam  port 
to  the  left  of  piston  H,  which  it  forces  with  the  in- 
tercepting valve  GGto  the  right.  In  this  position, 
as  shown  in  Fig.  134,  the  receiver 
openings  are  closed  by  the  pistons 
GO  and  the  poppet  valve  N  has 
been  opened  by  the  bell-crank  L, 
'thus  admitting  live  steam  through 
the  intercepting  valve  cylinder  and 
port  D  to  the  low-pressure  steam 
chest,  as  indicated  by  the  arrows.  Hence  it  is 
possible  to  obtain  the  full  pressure  of  live  steam 
in  the  low-pressure  cylinder  in  starting. 

After  one  or  two  revolutions  the  pressure  in  the 
receiver,  passing  down  through  the  small  connect- 
ing port  to  the  right  of  the  larger  piston  K1  (Fig. 
137)  overbalances  the  pressures  between  the  pis- 
tons, thus  moving  the  slide  valve  to  the  left,  the 
position  shown  in  Figs.  133  and  137.  According  to 
the  ordinary  action  of  a  slide  valve  this  reverses 
the  pressures  on  the  actuating  piston  77,  forcing  it 


OPERATION  OF  COMPOUND  LOCOMOTT  YES.         67 

to  the  left  and  opening  the  intercepting  valve. 
This  return  movement  of  the  actuating  piston  H 
detaches  the  bell-crank  L  from  the  poppet  valve 
N  and  allows  the  latter  to  close  before  the  inter- 
cepting valve  opens.  After  this  the  locomotive 
works  compound,  the  passage  of  steam  being 
through  the  high-pressure  cylinder  to  the  receiver 
and  thence  through  the  intercepting  valve  and 
low-pressure  cylinder  to  the  atmosphere,  as  pre- 
viously described. 

A  difficulty  met  with  in  many  of  the  earlier 
forms  of  compound  mechanism,  and  to  which  the 
reader's  attention  was  called  at  the  beginning  of 
this  chapter,  namely,  the  accumulation  of  dan- 
gerously high  pressure  in  the  receiver  when  run- 
ning with  the  throttle  closed,  was  overcome  in 
this  device  by  an  automatic  action  of  the  piston 
valve  M  and  the  differential  pistons  K  and  Kl 
(Fig.  137),  as  follows:  When  the  engine  is  using 
steam  the  regulating  valve  M  is  always  against 
the  right-hand  seat,  as  shown,  and  this  valve  only 
comes  into  use  when  running  without  working 
steam,  as  down  a  long  grade.  In  this  case,  if  the 
intercepting  valve  happened  to  be  closed,  the 
action  of  the  engine  would  cause  air-pressure  to 
accumulate  in  a  closed  receiver  as  there  would 
then  be  no  live  steam  available  to  cause  the 
actuating  device  to  open  the  intercepting  valve. 
Hence  it  is  arranged  so  that  air-pressure  in  the 
receiver  will  force  the  valve  M  to  the  left  and 
itself  take  the  place  of  live  steam  by  passing  to 
the  slide  valve  chamber  and  down  to  the  right 
side  of  the  actuating  piston  H,  moving  it  to  the 


68  ENGINEERS'  AND  FIREMEN'S  MANUAL. 


OPERATION  OF  COMPOrXD  LOCOMOTIVES.         69 

left  and  opening  the  intercepting  valve,  as  shown 
in  Fig.  133.  Thus  the  small  valve  M  acts  as  a 
safety  valve,  insuring  the  opening  of  the  inter- 
cepting valve  when  live  steam  is  not  being  used, 
and  preventing  the  danger  of  excessive  receiver 
pressure  or  the  lifting  of  the  high-pressure  slide 
valve  off  its  seat  when  the  engine  is  running  with 
steam  shut  off. 

SCHENECTADY  1892  DESIGN,  WITH  SOUTHERN   PACIFIC 
MODIFICATION. 

To  render  it  possible  to  run  the  engine  "simple" 
for  any  desired  period  in  starting,  or  to  obtain 
a  maximum  power  in  case  a  train  were  stall- 
ing on  a  heavy  grade,  the  Southern  Pacific  Co. 
in  1893  added  to  many  of  their  Schenectady  com- 
pounds of  the  1892  design,  a  separate  exhaust 
valve  located  in  the  smoke-box,  as  shown  in  Figs. 
139  and  140.  The  reverse  lever  in  the  cab,  when 
placed  in  either  of  its  extreme  positions,  caused 
this  valve  to  open  and  thereby  connect  the  re- 
ceiver directly  with  the  main  exhaust  pipe,  thus 
permitting  the  high-pressure  cylinder  to  exhaust 
through  the  receiver  directly  to  the  atmosphere, 
as  indicated  by  arrows  in  Fig.  139.  As  the  re- 
ceiver pressure  was  thus  kept  down  it  will  be 
readily  understood  from  the  preceding  description 
of  the  intercepting  valve  that  the  latter  will 
remain  in  starting  position  as  in  Fig.  134,  and 
hence  the  locomotive  will  work  as  a  simple  engine 
until  such  time  as  the  engineer  pulls  the  reverse 
lever  higher  up  on  the  quadrant  and  thereby 
closes  the  separate  exhaust  valve.  Then  the 


70  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

intercepting  valve  automatically  assumes  the 
compound  position,  as  in  Fig.  133,  for  reasons 
hereinbefore  explained. 

This  modification  of  the  two-cylinder  or  cross- 
compound  is  of  especial  note  inasmuch  as  it  was 
one  of  the  first  in  this  country  which  permitted 
the  working  of  the  locomotive  as  a  simple  engine 
for  any  desired  length  of  time,  at  the  will  of  the 
engineer.  Its  results  in  practical  operation  were 
to  greatly  reduce  the  jerking  of  trains  in  starting 
(then  a  very  serious  objection  to  many  com- 
pounds); it  gave  a  greater  maximum  power  at 
critical  periods,  and  was  withal  so  eminently  satis- 
factory that  the  reader  will  notice  the  majority 
of  the  builders  of  two-cylinder  compounds  in  this 
country  have  embodied  a  separate  exhaust  valve 
in  their  later  designs. 

SCHENECTADY  COMPOUND DESIGN  OF  1896. 

The  valve  arrangement  designed  in  1896  by 
Messrs.  A.  J.  Pitkin,  Vice-President  and  General 
Manager,  and  J.  E.  Sague,  Mechanical  Engineer  of 
the  Schenectady  Locomotive  Works,  and  used  as 
their  standard  construction  for  two-cylinder  com- 
pound locomotives,  will  be  made  clear  by  what 
follows. 

In  general  it  may  be  said  that  this  so-called 
"intercepting  valve' '  consists  of  four  separate 
parts,  namely:  (1)  An  intercepting  valve  proper, 
which  allows  steam  to  pass  to  the  low-pressure 
cylinder  from  either  the  receiver  or  the  boiler, 
according  to  its  position.  (2)  A  reducing  valve 
allowing  live  steam  at  only  a  reduced  pressure 


OPE  RATION  OF  COMPOUND  LOCOMOTT  VEX.         T I 

to  enter  the  low-pressure  cylinder  when  working 
simple.  (  3  )  An  independent  or  separate  exhaust 
valve  which,  when  open,  vents  the  exhaust  from 
the  high-pressure  cylinder  to  the  atmosphere 
through  the  exhaust  pipe  and  stack.  (4 )  A  small 
valve  K  inside  of  the  separate  exhaust  valve,  by 
the  use  of  which  the  latter  can  be  opened  more 
easily  and  gradually. 


By  the  arrangement  of  these  valves  the  engine 
can  be  started  and  run  either  compound  or  simple 
and  can  be  changed  from  compound  to  simple,  or 
the  reverse,  at  the  will  of  the  engineer,  with  the 
throttle  and  the  reverse  lever  in  any  position;  the 
engineer  has  only  to  move  a  small  three-way  cock 
in  the  cab  and  the  working  of  the  engine  changes 
very  smoothly  and  without  jerking  the  train. 


72  ENGINEERS'  AND  FIREMEN'S  MANUAL. 


OPERATION  OF  COMPOUND  LOCOMOTIVES,         73 


74          ENGINEERS'  ANU  Fl'liE  MEN'S  M^INUAL. 

Figs.  141  and  142  give  sections  of  smoke  arch 
and  cylinder  saddles  and  show  the  steam  passages, 
the  receiver  and  the  location  of  the  intercepting 
valve  in  the  saddle  of  the  low-pressure  cylinder  on 
the  right-hand  side  of  the  engine. 

It  will  be  noticed  by  the  dotted  lines  behind 
the  receiver  pipe  that  there  are  two  steam  pipes  as 
in  a  simple  engine,  but  the  one  (#)  leading  to  the 
intercepting  valve  on  the  low-pressure  side  is  much 
smaller  than  usual,  as  it  will  only  be  required  for 
use  at  low  speeds. 

Fig.  143  shows  a  vertical  section  lengthwise 
through  the  low-pressure  cylinder  saddle  and  the 
intercepting  valve  (as  if  they  were  cut  through  at 
MN  of  Fig.  142)  and  shows  the  intercepting 
and  the  separate  exhaust  valves  in  the  position 
taken  when  the  engine  is  working  simple  and  re- 
ceiving live  steam  in  both  cylinders.  Fig.  144  is 
a  section  through  the  dash-pot  of  Fig.  143. 

Fig.  145  gives  the  same  section  as  Fig.  143,  but 
shows  the  intercepting  and  the  separate  exhaust 
valves  in  the  position  taken  when  the  engine  is 
working  compound. 

Figs.  146  and  147  show  two  sections  crosswise 
of  the  intercepting  valve  at  points  indicated  re- 
spectively by  the  lines  cd  and  ab  of  Fig.  145.  Sec- 
tion cd  shows  the  passages  G  for  admitting  live 
steam  into  the  low-pressure  cylinder,  and  section 
a  b  shows  the  outlet  passage  U  from  the  sep- 
arate exhaust  valve  to  the  main  exhaust  pipe. 

The  part  which  each  portion  of  the  valve 
arrangement  performs  is  as  follows:  The  sepa- 
rate exhaust  valve,  when  open,  allows  the  steam 


OPERATION  OF  COMPOUND  LOCOMOTIVES.         75 

to  exhaust  from  the  high-pressure  cylinder 
to  the  atmosphere  without  going  through  the 
low-pressure  cylinder,  thus  working  the  en- 
gine simple;  when  it  is  closed,  the  high-press- 
ure exhaust  must  pass  through  the  low-press- 
ure cylinder,  thus  working  the  engine  com- 


/Section  c-d        Section  a- 


pound.  The  intercepting  valve  closes  the 
passage  between  the  two  cylinders  when  the  sep- 
arate exhaust  valve  is  open,  so  that  steam  can- 
not go  from  the  high-pressure  cylinder  to  the 
low-pressure  cylinder;  thus  doing  away  with 
back  pressure  on  the  high-pressure  piston  when 
the  engine  is  working  simple;  it  also  admits 
liye  steam  direct  from  the  dry-pipe  through 
the  reducing  valve  to  the  low-pressure  cylinder. 
When  the  separate  exhaust  valve  closes,  the 
intercepting  valve  automatically  opens  the  pas- 


76  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

sage  between  the  two  cylinders  and  cuts  off  the 
supply  of  live  steam  from  the  dry  pipe  to  the 
low-pressure  cylinder.  The  reducing  valve  works 
only  when  the  engine  is  working  simple  and 
throttles  the  steam  passing  through  it,  so  that 
the  pressure  of  steam  going  to  the  low-pressure 
cylinder  is  about  one-half  (or,  less,  according  to 
the  proportionate  sizes  of  the  two  cylinders)  of 
that  admitted  from  the  boiler  to  the  high-press- 
ure cylinder. 

The  reducing  valve  is  quite  heavily  cross-sec- 
tioned, while  the  long,  intercepting  valve  ap- 
pears next  lighter,  in  order  to  render  their  out- 
lines in  Figs.  143  and  145  readily  distinguishable. 
Examining  the  two  ends  of  the  intercepting  valve, 
it  will  be  seen  that  the  left  end,  exposed  to  the 
pressure  of  the  atmosphere  through  the  drip,  is 
only  about  three-fourths  as  large  as  the  right 
end  (between  the  bridges  E  R,  Fig.  143),  exposed 
to  the  receiver;  hence,  if  the  receiver  has  little 
or  no  pressure,  the  boiler  pressure  on  the 
shoulder  of  the  intercepting  valve  automatically 
carries  it  to  the  right,  as  shown  in  Fig.  143.  The 
reducing  valve  is  automatically  opened  because 
of  the  difference  in  area  of  its  two  ends  also.  The 
movement  of  each  of  these  valves  is  cushioned 
by  dash-pots,  as  shown.  The  separate  exhaust 
valve  is  operated  by  the  engineer  by  means  of  a 
three-way  cock  in  the  cab.  To  open  the  sepa- 
rate exhaust  valve  the  handle  of  the  three-way 
cock  is  thrown  so  as  to  admit  a  pressure  of  steam 
or  air  through  the  pipe  W  against  the  piston  J. 
Pulling  the  handle  back  relieves  the  pressure 


OPERATION  OF  COMPOUND  LOCOMOTI VES.         77 

against  piston  J  and  the  spring  shuts  the  valve, 
as  in  Fig.  145.  All  the  engineer  has  to  do  in 
connection  with  the  operation  of  the  valves  is  to 
pull  the  handle  of  the  three-way  cock  in  the  cab 
one  way  or  the  other,  according  as  he  wishes  the 
engine  to  run  simple  or  compound.  The  engi- 
neer uses  the  handle  under  the  following  condi- 
tions: 

To  Start  Simple. — Under  ordinary  conditions 
this  is  not  necessary,  but  if  the  maximum  power 
of  the  engine  is  needed  to  start  a  heavy  train,  the 
engineer  pulls  the  handle  of  the  three-way  cock 
so  as  to  admit  pressure  from  the  cab  through 
pipe  W  against  the  piston  J,  Fig.  145.  This  will 
force  piston  J  into  the  position  shown  in  Fig.  143, 
opening  the  separate  exhaust  valve  and  hold- 
ing it  open.  The  engine  throttle  now  being 
opened,  live  steam  at  boiler  pressure  enters  the 
chamber  E  from  the  small  steam  pipe  8  before 
mentioned  and  forces  the  intercepting  valve  to 
the  right  against  the  seat  FF,  as  shown  in  Fig. 
143.  The  exhaust  steam  from  the  high-pressure 
cylinder  now  passes  through  the  receiver  and  is 
exhausted  through  the  separate  exhaust  valve  to 
an  annular  chamber  U  connected  with  the  main 
exhaust  to  the  stack,  as  indicated  by  the  arrow  in 
Fig.  143.  (See  also  Fig.  147.)  Steam  also  enters 
the  low-pressure  cylinder  from  chamber  E  through 
the  reducing  valve  and  the  annular  ports  G  in 
the  intercepting  valve  (See  Figs.  143  and  146), 
and  is  exhausted  in  the  usual  way.  The  reducing 
valve  prevents  the  full  boiler  pressure  from  reach- 
ing the  low-pressure  cylinder,  As  will  be  seen  from 


78  ESUISEER&  ;LXD  FIREMEN  S  MASUAL. 

Figs.  143  and  145,  the  reducing  valve  is  partly  bal- 
anced by  its  smaller  left  end  being  open  to  the  at- 
mosphere through  a  small  groove  leading  to  the 
chamber  having  an  open  drip,  and  thus  the  boiler 
pressure  acting  on  the  unbalanced  area  throws  the 
valve  open — to  the  right.  When  the  pressure  in 
the  intercepting  valve  cavity  on  the  right  of  the 
reducing  valve  becomes  high  enough,  it  will  throw 
the  valve  to  the  left,  because  it  acts  on  the  whole 
area  of  the  valve;  the  result  is  that  the  steam  is 
throttled  to  the  proper  pressure  desired  for  the 
low-pressure  cylinder. 

To  Work  Compound. — Having  started  the  train, 
when  the  engineer  wishes  to  change  the  engine 
from  simple  working  to  compound,  he  pushes  the 
handle  of  the  three-way  cock  to  its  first  position 
which,  relieving  the  pressure  on  piston  J  through 
pipe  W,  allows  the  spring  to  act  to  the  right  and 
close  the  separate  exhaust  valve,  as  in  Fig.  145. 
As  soon  as  this  valve  is  closed  the  pressure  in  the 
receiver,  having  no  outlet,  rises  and  presses  the 
intercepting  valve  to  the  left  against  the  pressure 
from  chamber  E,  which  acts  only,  as  stated, 
upon  the  shoulder  of  the  intercepting  valve.  The 
receiver  pressure  holds  the  intercepting  valve  to 
the  left,  as  shown  in  Fig.  145,  thereby  closing  the 
ports  6r  and  opening  a  free  passage  from  the 
receiver  to  the  low-pressure  cylinder  as  indicated 
by  the  arrows,  and  the  engine  works  compound. 
While  working  compound,  which  is  the  usual  way 
of  working  the  engine,  both  the  reducing  and  the 
intercepting  valves  are  held  to  the  left  against 
ground  joint  seats.  This  should  prevent  any 


OPERATION  OF  COMPOUND  LOCOMOTI VES.         7  9 

steam  which  might  leak  by.  the  packing  rings 
from  constantly  escaping  at  the  drip. 

To  Change  from  Compound  to  Simple. — With 
the  engine  running  compound,  if  the  engineer 
wishes  to  change  to  simple  because  of  a  very 
heavy  grade,  he  has  only  to  pull  the  three-way 
cock  handle  to  the  same  position  as  for  starting 
simple.  Then  piston /first  opens  the  small  valve 
K  and  then  the  separate  exhaust  valve.'  The 
small  valve  ^relieves  the  pressure  more  gradually 
than  if  the  larger  valve  were  opened  at  once. 
As  soon  as  the  separate  exhaust  valve  is  opened 
the  pressure  in  the  receiver  escapes  through  it 
and  becomes  so  low  that  the  intercepting  valve  is 
again  forced  to  the  right  (as  in  Fig.  143)  against 
its  seat  F  by  the  steam  pressure  from  chamber 
E,  and  the  engine  works  simple  as  in  starting. 

To  Start  as  an  Automatic  Compound. — If  the 
separate  exhaust  valve  is  left  closed,  as  in  Fig. 
145,  the  engine  will  start  as  an  automatic  com- 
pound when  the  throttle  is  opened,  for  the 
pressure  from  chamber  E  will  force  the  intercept- 
ing valve  to  the  right,  as  in  Fig.  143,  thus  admit- 
ting live  steam  through  the  reducing  valve  and 
ports  G  to  the  low-pressure  cylinder,  while  at  the 
same  time  the  high-pressure  cylinder  exhausts 
into  a  closed  receiver  for  a  few  strokes.  This 
pressure,  accumulating  in  the  receiver,  will  then 
automatically  close  the  ports  G  by  moving  the 
intercepting  valve  to  the  left,  as  in  Fig.  145,  and 
the  engine  thereafter  runs  compound. 

Accidents  to  Schenectady  Compounds — the  Auto- 
matic Compound  of  1892.  What  should  be  done 


80  ENGINEERS'  AND  FIREMEN' X  MANUAL. 

in  case  of  a  break-down  on  the  road,  necessi- 
tating the  disconnecting  of  the  high-pressure 
side?  If  but  a  short  distance  to  go  and  a  slow 
speed  would  suffice,  clamp  the  high-pressure 
slide  valve  in  center  and  permit  the  engine  to 
run  by  the  admission  of  live  steam  through 
the  small  pipe  *SYl  and  the  poppet  valve  N  to  the 
high-pressure  cylinder  (Figs.  133  and  134).  If 
the  intercepting  valve  is  out  of  order,  block  the 
poppet  valve  ^\T  open,  that  is,  up.  If  it  were  re- 
quired to  run  at  considerable  speed,  this  small 
pipe  Sl  would  give  insufficient  supply,  in  which 
case  the  high-pressure  slide  valve  should  be 
blocked  clear  back  (much  farther  than  its  ordi- 
nary travel  carries  it),  so  as  to  uncover  the 
exhaust  port,  thus  admitting  live  steam  direct 
to  the  receiver.  If  the  steam  chest  is  large 
enough  to  place  the  high-pressure  valve  as 
described,  and  the  intercepting  valve  is  not  de- 
ranged, the  engine  would  run  at  full  speed  with 
the  low-pressure  side.  If  out  of  order,  the  inter- 
cepting valve  should  be  held  open  (in  the  position 
as  shown  in  Fig.  133)  by  clamping  the  stem  be- 
tween the  stuffing  boxes.  In  all  cases  the  throttle 
should  be  handled  easily  to  prevent  a  too  rapid 
flow  of  boiler  pressure  to  the  large  low-pressure 
cylinder  and  the  consequent  liability  of  jerking 
the  train  or  causing  damage  to  this  cylinder. 

What  should  be  done  if  it  becomes  necessary 
to  take  down  the  low-pressure  side  of  the  engine? 
The  engine  could  be  moved  a  short  distance  with 
the  cylinder  cocks  open  or  the  indicator  plugs  re- 
moved on  the  high-pressure  side,  but  as  most  en- 


OPERATION  OF  COMPOUND  LOCOMOTI VES.         81 

gines  of  this  class  have  either  a  large  steam  chest 
or  an  "Allen"*  ported  slide  valve,  the  valve  can 
be  clamped  back  far  enough  to  uncover  the  low- 
pressure  exhaust  port,  and  thus  run  at  full  speed. 
If  this  cannot  be  done,  block  both  the  low-press- 
ure crosshead  and  valve  clear  back  and  unscrew 
the  relief  valves  or  take  off  the  front  cylinder 
head  on  that  side  to  make  an  exhaust  opening 
from  the  receiver.  If  the  intercepting  valve  is 
out  of  order,  it  must  be  securely  clamped -open, 
as  in  Fig.  133,  otherwise  the  opening  between 
the  receiver  and  the  low-pressure  steam  chest 
would  be  closed. 

In  this  last  procedure,  with  the  exhaust  other 
than  through  the  stack,  would  the  engine  steam 
with  much  of  a  train?  No;  but  a  limited  amount 
of  steam  could  be  maintained  by  the  use  of  the 
blower  for  creating  draught. 

What  would  be  the  effect  of  the  removal  of  the 
slide  valve  on  the  disabled  side?  This  would 
give  a  free  port  opening  under  all  circumstances, 
but  would  generally  consume  too  much  time  to 
be  practicable. 

What  prevents  the  leakage  of  live  steam  into 
the  receiver  when  the  intercepting  valve  is  closed, 
as  in  Fig.  134,  there  being  no  packing  rings  in  the 
two  pistons  6r6r?  The  live  steam  pressure  acts 
from  below  when  starting,  so  as  to  hold  these 
pistons  tight  against  ports  of  the  receiver.  Fig. 
135  illustrates  this  clearly,  if  the  intercepting 


*See  illustrations  in  Part  First  of    the  Manual,  showing  the 
'Allen"  slide  valve. 


&2  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

valve  were  there  shown  closed,  as  live  steam 
would  then  be  below  pistons  GG. 

What  would  be  the  result  if  the  wiper  L  would 
strike  the  poppet  valve  N  (Figs.  133  and  134) 
before  the  intercepting  valve  pistons  GG  closed 
their  ports?  Live  steam  would  blow  through  to 
the  receiver  and  produce  a  back  pressure  on  the 
high-pressure  side. 

How  can  this  be  prevented?  Pistons  GG  have 
sufficient  lap  to  allow  of  their  closing  before  the 
wiper  L  strikes  the  poppet  valve  N,  and  the 
adjustable  tappet  on  the  intercepting  valve  stem 
should  be  set  so  as  to  cause  this.  If  the  tappet  is 
set  too  far  back,  valve  N  would  not  be  opened  at 
all  and,  as  a  consequence,  no  live  steam  would  be 
admitted  to  the  low-pressure  cylinder  in  starting. 

If  the  operating  piston  H  should  break,  what 
position  would  the  intercepting  valve  probably 
take  ?  On  account  of  the  unbalanced  area  of  the 
stem,  it  would  probably  move  open  to  the  left 
as  for  compound  working,  Fig.  133. 

Accidents  to  Schenectady  design  of  1892,  with 
Southern  Pacific  Modifications. — If  it  became 
necessary  to  disconnect  the  high-pressure  side  of 
the  engine,  what  should  be  done?  The  same  as 
with  the  1892  Schenectady  system. 

Would  there  be  any  difference  in  case  the  low- 
pressure  side  broke  down?  Yes;  disconnect  the 
broken  side  as  usual  (see  instructions  for  simple 
engines  in  Part  First  of  the  Manual)  and  run  with 
reverse  lever  in  full  gear,  if  for  a  short  distance  or 
a  low  speed  only  is  required.  If  it  is  necessary  to 
run  for  a  considerable  distance  at  a  good  speed,  it 


OPERATION  OF  COMPOUND  LOCOMOTIVES.         83 

would  be  advisable  to  disconnect  the  separate  ex- 
haust valve  levers  from  their  connection  to  the 
reach-rod  and  properly  secure  them  in  either  ex- 
treme position,  so  as  to  hold  the  valve  open.  The 
engine  can  then  be  "hooked-up,"  that  is,  the  re- 
verse lever  pulled  up  toward  its  central  position, 
to  correspond  to  the  demands  of  the  service. 

Accidents  to  Schenectady  Compounds — design  of 
1896. — What  should  be  done  in  case  the  high- 
pressure  side  had  to  be  disconnected  ?  Ordinari]  y , 
open  the  separate  exhaust  valve  *  and  do  nothing- 
different  than  with  a  simple  engine;  but  to  obtain 
greater  speed  than  the  supply  of  live  steam  to 
the  low-pressure  cylinder  through  its  small  steam 
pipe  would  permit,  the  high-pressure  valve  should 
be  secured  in  such  a  position,  if  possible,  as  will 
uncover  its  exhaust  port,  thereby  admitting  live 
steam  to  the  receiver  and  thence  to  the  low- 
pressure  cylinder.  In  this  case  leave  the  separate 
exhaust  valve  closed  and  handle  the  throttle 
easily  so  as  not  to  cause  constant  opening  of  the 
safety  valves  on  the  low-pressure  side. 

What  is  necessary  with  the  low-pressure  side 
disconnected?  Open  the  separate  exhaust  valve 
and  allow  the  high-pressure  cylinder  to  exhaust 
to  the  stack  through  its  connection.  While  con- 
siderable train  could  thus  be  handled,  it  would 
not  be  done  at  anything  but  a  slow  speed,  unless 
the  low-pressure  slide  valve  were  placed  so  as  to 


*  While  not  absolutely  necessary  to  open  the  separate  exhaust 
valve  for  this  case,  it  is  best  to  do  so  that  there  may  be  no 
accumulation  of  pressure  in  the  receiver  should  the  high-pressure 
valve  leak. 


84  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

uncover  its  exhaust  port  and  the  separate  ex- 
haust valve  left  closed. 

What  is  done  to  prevent  full  boiler  pressure 
from  reaching  the  low-pressure  cylinder  in  case 
the  reducing  valve  becomes  defective  or  broken? 
Pop  or  safety  valves  are  placed  on  the  chest  and 
both  heads  of  the  low-pressure  cylinder  and  they 
are  set  at  about  one  hundred  pounds,  the  highest 
pressure  deemed  advisable  in  so  large  a  cylinder. 

In  case  of  a  broken  intercepting  valve  what 
precautions  should  be  taken?  Run  the, engine 
compound  only  and  do  not  stop  the  engine  with 
the  low-pressure  side  on  center. 

Why  must  the  oil  dash-pot  be  kept  filled  with 
oil?  The  flow  of  oil  from  one  side  of  the  dash- 
pot  piston  to  the  other  prevents  sudden  move- 
ments of  and  serious  jars  to  the  intercepting  valve. 

How  can  the  rapidity  of  this  movement  be  reg- 
ulated? By  a  greater  or  less  opening  of  the  valve 
P,  Figs.  143  and  144,  as  this  valve  regulates  the 
flow  of  oil  from  one  side  of  the  dash-pot  piston  to 
the  other.  A  slight  opening  causes  a  slow  move- 
ment, while  a  wide  opening  makes  possible  a  too 
rapid  movement. 

What  would  be  most  liable  to  cause  breakage 
to  the  intercepting  valve  ?  Allowing  the  oil  dash- 
pot  to  become  partially  or  wholly  empty. 

What  kind  of  oil  should  be  used  in  this  dash- 
pot?  Only  mineral  oil,  thinner,  if  anything,  than 
ordinary  engine  oil. 

What  is  the  purpose  of  the  key  shown  in  the 
dash-pot  (Fig.  144)?  To  prevent  the  intercepting 
valve  from  turning  around. 


OPERATION  OF  COMPOUND  LOCOMOTI VES,         85 

With  this  compound,  what  pressure  from  the 
cab  is  used  to  operate  the  separate  exhaust  valve  ? 
Either  air  or  steam. 

Why  is  air  pressure  generally  considered  pref- 
erable? On  account  of  the  absence  of  moisture 
therein.  As  the  separate  exhaust  valve  piston  J 
and  its  cylinder  (Figs.  143  and  145)  project  from 
the  front  of  the  cylinder  saddle  and  are  exposed  to 
currents  of  cold  air,  the  use  of  steam  therein  and  a 
lack  of  proper  drainage  might  cause  them  to  freeze 
in  cold  weather. 

What  objection  is  there  to  the  use  of  air? 
Should  the  air  pump  stop  or  the  pressure  other- 
wise become  exhausted,  as  in  switching  and  pick- 
ing up  a  large  number  of  air-brake  cars,  there 
might  be  insufficient  pressure  to  hold  the  valve 
open  against  the  receiver  pressure. 

How  is  this  objection  overcome  when  air  is 
used  for  this  purpose?  Besides  the  air  connec- 
tion to  the  three-way  cock  in  the  cab,  there  is  a 
steam  connection;  closing  the  one  and  opening 
the  other,  quickly  furnishes  an  alternative  press- 
ure for  operation. 

What  would  be  the  result  if  both  the  steam  and 
the  air  connections  were  left  open  ?  There  would 
be  no  effect  upon  the  engine  itself,  but  the  steam 
would  fill  the  whole  air-brake  system  with  wTater 
and  seriously  affect  the  operation  of  the  brakes. 


THE    PITTSBURG    COMPOUND. 

The  Pittsburg  Locomotive  Works  have  been 
one  of  the  largest  builders  of  two-cylinder  or 
cross-compound  locomotives  in  this  country. 
Their  location  of  the  intercepting  valve  in  the 
saddle  of  the  high-pressure  cylinder  instead  of 
the  low-pressure  cylinder  is  an  arrangement 
which  obviates  the  necessity  of  a  second  steam 
pipe  for  admitting  live  steam  to  the  intercepting 
valve  and  low-pressure  cylinder  when  it  is  de- 
sired to  work  the  engine  non-compound. 

With  the  valve  mechanism  which  will  be 
shown  and  described  in  what  follows,  when  the 
reverse  lever  is  either  in  full  forward  or  back-up 
gear  and  the  throttle  opened,  the  engine  starts 
by  the  admission  of  live  steam  into  both  cylin- 
ders and  with  an  open  exhaust  passage  from  each 
cylinder  to  the  stack.  The  live  steam  admitted 
to  the  low-pressure  cylinder  is  sufficiently  re- 
duced in  pressure  by  passing  through  a  reducing 
valve  to  cause  the  engine  to  have  the  same  power 
that  a  simple  locomotive  would  have  with  two 
cylinders  the  size  of  the  high-pressure  cylinder. 
When  the  reverse  lever  is  "  hooked-up,"  or  drawn 
toward  the  center,  one  or  more  notches,  it  me- 
chanically works  an  operating  valve  and  piston 
near  the  cab,  which  throws  the  intercepting 
valve  into  position  for  compound  working. 
There  is  a  hand  lever  in  the  cab,  as  shown  in 
Fig.  148,  which  can  be  used  to  move  the  inter- 

(86) 


OPERATION  OF  COMPOUND  LOCOMOTIVES.        87 


88          ENGINEERS'  ;\ND  FIREMEN'S  MANUAL. 

cepting  valve  in  case  of  derangement  of  the  op- 
erating device,  or  other  necessity.  However, 
the  engine  will  only  start  simple  when  the  in- 
tercepting valve  is  placed  in  proper  position,  as 
this  valve  does  not  automatically  assume  simple 
position  of  its  own  volition.  Fig.  148  gives  the 


Yi0rz  of  z/afoes  w/Zex 


general  arrangement  and  shows  the  position  of 
the  intercepting  and  reducing  valves  in  the 
saddle  of  the  high-pressure  cylinder  on  the  right- 
hand  side  of  the  engine,  the  lever  connections  be- 
tween the  intercepting  valve  and  the  operating 
cylinder  near  the  cab,  and  the  means  of  moving 


OPERATION  OF  COMPOUND  LOCOMOTIVES. 


89 


the  operating  valve  by  its  attachment  to  the 
reach-rod.  The  operating  piston  can  be  actuated 
either  by  air  or  steam  pressure,  the  former  being 
preferable,  especially  in  cold  climates. 

Figs.  149  and  150  show  on  a  larger  scale  the 
same  section  through  the  valves  in  the  saddle. 


In  Fig.  149  the  intercepting  and  the  reducing 
valves  are  in  position  for  working  simple,  while 
in  Fig.  150  they  are  shown  in  compound  position. 
Port  S  is  the  passage  from  the  steam  pipe  to  the 
high-pressure  steam  chest,  and  port  E  the  ex- 
haust passage  from  the  high-pressure  cylinder; 
port.R  is  the  opening  into  the  receiver;  port  B 
leads  to  the  atmosphere  through  the  stack,  being 


90  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

an  independent  exhaust  for  the  high-pressure  cyl- 
inder. Port  C  is  a  branch  from  the  main  steam 
port  S,  and  carries  live  steam  to  the  reducing  valve 
&  for  use  in  the  low-pressure  cylinder  when 
needed. 

When  the  intercepting  valve  is  moved  to  the 
left  in  position  for  working  simple,  as  shown  in 
Fig.  149,  steam  from  the  high-pressure  exhaust^1 
passes  through  the  intercepting  valve  (between 
its  two  piston  ends)  and  to  the  atmosphere 
through  the  independent  exhaust  B.  At  the  same 
time  live  steam  from  C  opens  the  reducing  valve 
6r,  as  the  valve  is  then  unbalanced  by  its  left  end 
being  larger  than  its  right,  and  passes  through  the 
intercepting  valve  chamber  D  and  the  receiver  E 
to  the  low-pressure  cylinder.  The  engine  is  thus 
made  a  simple  engine  with  live  steam  admission 
and  independent  exhausts  for  each  cylinder,  as 
indicated  by  the  arrows  in  Fig.  149. 

The  reducing  valve  6r,  when  in  use,  only  allows 
a  portion  of  the  full  pressure  to  pass  into  the 
receiver,  for,  when  the  pressure  in  the  intercepting 
valve  chamber  D  (Fig.  149)  becomes  equal  to 
about  half  that  of  the  boiler,  it  acts  against  the 
larger  left-hand  end  of  the  reducing  valve  and 
forces  it  closed — to  the  right — thereby  throttling 
the  steam. 

The  intercepting  valve  moved  ahead,  or  in  com-  > 
pound  position,  as  in  Fig.  150,  holds  closed  the 
reducing  valve  G,  thus  shutting  off  the  live  steam 
supply  to  the  low-pressure  cylinder.  At  the  same 
time  it  closes  the  independent  exhaust  opening  B, 
instead  opening  the  ports  to  the  receiver  R  and  con- 


OPERATION  OF  COMPOUND  LOCOMOTI VES.         9 1 

necting  the  high-pressure  exhaust  E  therewith 
around  the  stem  of  the  intercepting  valve.  As  the 
other  end  of  the  receiver  leads  to  the  low-pressure 
steam  chest,  the  high-pressure  exhaust  thus  be- 
comes the  supply  steam  for  the  low-pressure  cyl- 
inder and  the  engine  works  as  a  compound,  the 
flow  being  indicated  by  the  arrows,  Fig.  150. 

From  the  above  description  it  will  be  observed 
that  the  office  of  the  intercepting  valve  is  to  convert 
the  locomotive  from  simple  to  compound,  or  the 
reverse.  The  duty  of  the  reducing  valve  is,  when 
the  engine  is  working  single-expansion,  to  reduce 
the  live  steam  from  the  boiler  to  a  pressure  in- 
versely proportional  to  the  ratios  of  the  two  cyl- 
inders before  delivering  it  to  the  receiver  and  low- 
pressure  cylinder,  thus  making  the  crosshead  loads 
equal  on  each  side  of  the  engine. 

Accidents  to  Pittsburg  Compounds. — If  the  engine 
broke  down  and  it  became  necessary  to  disconnect 
either  side,  could  the  engine  be  run  successfully 
on  one  side?  Yes,  it  would  be  more  powerful  than 
a  simple  engine  under  similar  circumstances  and 
could  develop  good  speed,  inasmuch  as  the  inde- 
pendent exhaust  ports  B  (Fig.  149)  are  of  con- 
siderable size. 

With  the  high-pressure  side  disconnected,  how 
should  the  engine  be  run?  The  intercepting 
valve  should  be  placed  in  simple  position  (as  in 
Fig.  149)  by  leaving  the  reverse  lever  in  full 
gear.  Live  steam  would  then  pass  through  the 
reducing  valve  to  the  low-pressure  cylinder  and 
exhaust  in  the  usual  way.  The  high-pressure 
valve  should,  of  course,  be  clamped  in  the  center. 


92  ENGINEERS'  AND  FIREMEN'S  MANUAL. 

If  the  low-pressure  side  were  disconnected, 
how  conld  the  engine  be  run?  Clamp  the  low- 
pressure  valve  in  the  center  so  as  to  cover  all 
ports  and  work  simple,  with  engine  in  full  gear. 
Steam  would  then  be  admitted  as  usual  through 
the  steam  pipe  to  the  high-pressure  cylinder  and 
exhausted  through  the  intercepting  valve  cavity 
and  the  independent  exhaust  jB,  Fig.  149. 

In  both  of  these  cases  what  would  be  necessary 
in  order  to  run  at  considerable  speed?  To  close 
the  small  valve  which  supplies  steam  to  the  op- 
erating device.  The  hand  lever  can  then  be 
used  for  operating  and  thus  the  reverse  lever 
hooked  up  to  a  shorter  cut-off.  The  intercepting 
valve  levers  should  be  securely  fastened  in 
simple  position. 

With  a  demolished  steam  chest  on  the  low- 
pressure  side,  could  the  engine  be  fixed  to  run  in 
any  way  different  from  such  an  accident  to  a 
simple  locomotive?  Yes.  Proceed  the  same  as 
before  described  when  the  lo\v-pressure  side  is 
disconnected,  except  that  the  reducing  valve  must 
now  be  held  closed.  This  could  be  done  by  tight- 
ening up  the  nuts  on  the  outside  stem  of  the 
reducing  valve,  or  by  inserting  washers  or  a  block 
under  them.  This  same  procedure  could  be  fol- 
lowed for  broken  valve  yoke,  or  valve  stem  bro- 
ken off  inside  of  steam  chest,  under  which 
circumstances  it  is  difficult  to  cover  ports  with- 
out taking  up  the  steam  chest  cover. 

What  should  be  done  if  the  reducing  valve 
became  broken?  Endeavor  to  start  compound, 
that  is,  with  the  lever  hooked  up  three  or  four 


OPERATION  OF  COMPOUND  LOCOMOTIVES.          93 

notches,  but  if  necessary  to  run  simple,  use  very 
light  throttle  or  reduce  the  amount  of  boiler 
pressure  carried. 

If  the  packing  rings  in  the  intercepting  valve 
blew  badly,  how  could  it  be  detected?  First  see 
that  the  slide  valves  are  tight,  then  shut  off  the 
supply  of  air  or  steam  from  the  operating  cylin- 
der by  closing  the  small  globe  valve  in  the  cab, 
pull  the  intercepting  valve  clear  back  (by  means 
of  the  hand  operating  lever)  into  simple  position, 
as  in  Fig.  149,  and  open  the  throttle,  still  leaving 
the  valves  in  the  center.  The  blow  would  show 
in  the  stack.  However,  it  is  an  easy  matter  to 
remove  the  intercepting  valve,  by  taking  off  the 
back  cap,  and  examine  the  packing  rings,  and 
this  should  be  done  frequently,  that  no  broken 
pieces  may  catch  in  the  ports. 

With  this  design  of  compound,  is  it  necessary 
to  caution  the  engineer  against  the  bad  practice 
of  operating  the  engine  in  simple  position  for 
too  great  a  length  of  time,  or  at  high  speeds  ? 
No;  for,  if  the  small  valve  in  the  cab  which  sup- 
plies pressure  to  the  operating  device  be  open, 
to  run  the  engine  simple,  requires  that  the  reverse 
lever  be  at  full  stroke,  and  no  competent  man 
would  work  the  engine  thus  longer  than  neces- 
sary. 

In  starting,  where  should  the  reverse  lever  be 
placed?  In  full  motion  to  allow  the  intercepting 
valve  to  close  and  the  reducing  valve  to  open 
and  admit  live  steam  to  the  low-pressure 
cylinder. 


RICHMOND    COMPOUND. 


The  Richmond  compound  locomotive  (some- 
times termed  the  "Mellin"  system,  as  it  is  built 
under  those  patents)  is  also  of  the  two-cylinder  or 
cross-compound  type  and  belongs  to  the  class  of 


convertible  compounds.  The  large  low-pressure 
cylinder  is  placed  on  the  right-hand  side  of  the 
engine,  and  within  its  saddle,  as  shown  in  Fig.  151, 
is  located  the  special  valve  mechanism  by  which 

(94) 


OPERATION  OF  COMPOUND  LOCOMOTl  YES.         95 

the  engine  starts  with  the  admission  of  live  steam 
to  both  cylinders  and  thereafter  automatically 
changes  to  compound,  or  may  be  converted  back  to 
simple  any  time  at  the  will  of  the  engineer.  With- 
out any  movement  of  valves  by  the  engineer,  the 
locomotive  is  an  "automatic"  compound,  that  is, 
changes  to  working  compound  after  the  first  stroke 
or  two;  but  the  movement  by  him  of  a  three-way 
cock  in  the  cab,  causes  the  opening  of  a  separate 
exhaust  valve  (sometimes  called  the  "emergency 
valve")  for  the  high-pressure  cylinder,  and  thus 
the  engine  can  be  run  simple  as  long  as  he  thinks  it 
advisable,  or,  if  disabled,  can  be  brought  in  with 
one  side  like  a  single-expansion  locomotive. 

The  device  called  the  intercepting  valve  really 
consists  of  three  separate  and  distinct  valves,  as 
shown  in  Figs.  152  and  153. 

The  intercepting  valve  proper  is  marked  G  and 
is  a  double  poppet  valve  with  its  two  seats  of  un- 
equal areas,  and  has  a  stem  extending  back  and 
connecting  with  the  piston  P  of  an  air  dash-pot. 
The  intercepting  valve  moved,  or  opened,  as  in 
Fig.  153,  connects  the  receiver  R  with  the  low- 
pressure  steam-chest  port  L,  while  if  closed,  as  in 
Fig.  152,  it  cuts  off  this  communication  and  opens 
the  receiver  R  to  the  cavity  U. 

The  reducing  valve  is  a  long  annular  valve  sur- 
rounding the  intercepting  valve  stem  and  closes 
by  moving  to  the  left.  When  open,  it  admits  live 
steam  from  chamber  S  to  the  low-pressure  steam 
chest  cavity  L;  when  closed,  it  cuts  off  this  com- 
munication. 

The  separate  exhaust  or  "emergency"  valve  E  is 


96 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


an  ordinary  bevel-seated  wing-valve  with  its  right- 
hand  end  in  the  forni  of  a  piston.  Steam  pressure 
from  a  three-way  cock  in  the  cab,  if  admitted 
against  this  piston,  forces  the  separate  exhaust 
valve  open,  thereby  connecting  the  cavity  U  with 
the  main  exhaust  cavity  C;  without  pressure  on 
this  piston,  the  spring  F  again  seats  the  valve. 


JStig 


The  reducing  valve  is  shown  heavily  cross-sec- 
tioned, the  intercepting  valve  is  next  as  dark. 

The  operation  of  the  valves  is  as  follows:  Sup- 
pose the  engine  to  be  at  rest  after  running  com- 
pound with  the  valves  in  position  as  shown  in 
Fig.  153.  Upon  opening  the  engine  throttle,  steam 
passes  not  only  to  the  high-pressure  side  in  the 


OPERATION  OF  COMPOUND  LOCOMOTIVES. 


97 


usual  manner,  but  also  through  a  branch  steam 
pipe  S  (Fig.  151)  to  the  annular  cavity  S3  (Fig. 
153),  bears  against  the  shoulder  e  of  the  reduc- 
ing valve  at  the  seat  B  (Figs.  153  and  154)  and 
forces  the  latter  valve  to  the  right,  and  with  it  the 
intercepting  valve,  to  the  position  in  which  they 
are  shown  in  Fig.  152.  As  soon  as  the  enlarged 
end  of  the  reducing  valve  passes  the  edge  h  of  the 


from 


port  L  (see  also  Fig.  154),  live  steam  is  admitted 
to  L  and  thence  to  the  low-pressure  cylinder,  as  in- 
dicated by  the  arrows.  As  we  assumed  the  engi- 
neer had  not  opened  the  separate  exhaust  valve,  it 
will  remain  closed  instead  of  open,  as  Fig.  152  shows 
it;  otherwise  that  figure  would  show  the  valve  posi- 
tions at  this  stage.  Thus,  while  the  receiver  R  is  in 


98 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


communication  with  the  cavity  f7,  there  is  no 
outlet  from  the  latter,  and  one  or  two  exhausts 
from  the  high-pressure  cylinder  into  the  closed 
receiver  R  will  produce  sufficient  pressure  to  act 
against  the  larger  left-hand  face  of  the  inter- 
cepting valve  G  and  cause  it  to  move  to  the  left, 
shoving  with  it  and  closing  the  reducing  valve, 
as  shown  in  Fig.  153.  Now  the  receiver  pressure 
becomes  the  supply  for  the  low-pressure  cylinder 
as  shown  by  the  arrows,  and  the  engine  works 
compound  thereafter.  The  engine  will  start  all 
ordinary  trains  in  this  manner  but  if  the  train 


to  be  started  is  a  very  heavy  one,  or  such  a  train 
is  threatened  with  stalling  while  ascending  a 
heavy  grade,  the  handle  of  the  three-way  cock 
in  the  cab  should  be  turned  to  open  the  separate 
exhaust  valve  E.  This  would  vent  the  pressure 
in  chamber  U  to  the  main  exhaust  C,  as  indicated 
by  the  arrows  in  Fig.  152.  If  the  engine  were 
starting,  no  pressure  could  accumulate  in  the  re- 
ceiver R  on  account  of  this  vent  to  the  atmosphere, 
and  hence  all  valves  would  remain  as  in  Fig.  152 
and  the  engine  would  continue  to  work  simple 
until  such  time  as  the  engineer  closed  the  separate 


OPERATION  OF  COMPOrXD  LOCOMOTIVES. 


99 


exhaust  valve  E  by  means  of  his  cab  valve.  If, 
however,  the  engine  were  stalling  working  com- 
pound (Fig.  153)  and  the  engineer  opened  the 


.  sss. 


separate  exhaust  valve  E,  the  removal  of  press- 
ure from  chamber  U  would  cause  the  intercepting 
valve  to  close,  assisted  by  the  live  steam  pressure 
on  the  reducing  valve  shoulder,  and  thus  all  valves 


T/te  J?ic£m0Ke?  Compound. 


would  remain  as  in  Fig.  152  until  the  engineer 
desired  to  work  compound  again.  Then  he 
would  simply  close  the  separate  exhaust  valve  E 


100         ENGINEERS'  AND  FIREMEN'S  MANUAL. 

and  permit  the  valves  to  automatically  assume 
compound  working  by  the  accumulation  of  press- 
ure in  the  receiver  R. 

The  annular  shaped  reducing  valve  appears  so 
much  like  an  inoperative  sleeve  around  the  in- 
tercepting valve  stem  that  the  separate  sketch  is 
made  on  a  larger  scale  in  Fig.  154,  in  order  to  illus- 
trate its  principle  the  more  clearly.  Live  steam 
from  S  bearing  against  the  shoulder  e  would  force 
the  reducing  valve  from  the  position  in  the  cut  to 
the  right  until  shoulder  e  had  passed  the  edge  h 
of  the  chamber  L  and  live  steam  thus  be  admitted 
to  L  and  the  low-pressure  cylinder.  As  soon  as 
the  pressure  in  L  became  sufficiently  great,  say 
about  half  that  in  S,  the  valve  would  close 
partly  so  that  only  the  desired  proportion  of  the 
full  boiler  pressure  would  be  admitted  to  the 
low-pressure  cylinder. 

The  injurious  action  of  large  pistons  in  pump- 
ing air  when  the  engines  are  shut  off,  as  previously 
mentioned  under  "Classes  of  Compound  Locomo- 
tives and  their  General  Construction,"  is  prevented 
in  compound  engines  of  the  Richmond  type  by 
the  use  of  "by-pass"  valves  located  in  the  casting 
of  low-pressure  cylinder,  as  shown  in  Fig.  151, 
and  further  shown  in  detail  in  their  two  positions 
by  Figs.  155  and  156.  They  work  automatically 
by  the  opening  and  closing  of  the  engine  throttle, 
their  construction  and  operation  being  as  follows: 
The  outer  ends  of  the  two  piston  valves  W  are 
connected  by  the  passages  AA  with  the  induction 
ports  of  the  low-pressure  cylinder  and  their  inner 
ends  are  connected  by  the  passages  00  with  the 


OPERATION  OF  COMPOUND  LOCOMOTIVES.        101 

steam  ports.  The  pistons  PP  simply  act  in  the 
cavities  of  the  valves  as  dash-pots  to  prevent  slam- 
ming of  the  valves. 

Open  the  engine  throttle,  and  live  steam  from 
the  induction  ports  through  the  passages  AA 
drives  the  valves  W  toward  each  other  against 
their  seats  and  communication  between  -the 
two  steam  ports  0  and  0  is  closed,  as  in  Fig.  156. 
With  the  throttle  closed,  the  least  vacuum  in  the 


steam  chest,  acting  at  A  A,  is  aided  by  compression 
in  the  cylinder  through  ports  00,  and  the  "by- 
pass" valves  move  outward  to  the  position  shown 
in  Fig.  155.  In  this  position  the  two  steam  ports 
00  are  connected  and  air  passes  freely  from  one 
side  of  the  piston  to  the  other — the  purpose  for 
which  they  are  applied. 

The  necessity  for  very  large  port  openings  for 
the  large  low-pressure  cylinders  was  mentioned 
under  the  general  discussion  of  compound  loco- 


102 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


motives  and  it  was  there  stated  that  auxiliary 
ported  valves  of  the  "Allen"  type  were  used  to 
give  a  double  port  opening  to  the  cylinders  in  the 
early  part  of  the  admission  period. 

One  Richmond  design  of  slide  valve  employs 
this  auxiliary  port  not  only  for  double  early  ad- 
mission, but  also  to  give  a  double  opening  in  the 
early  exhaust  period.  Fig.  157  shows  the  design 
and  gives  the  dimensions.  It  will  be  noticed  that 


the  "Allen,"  or  supplementary,  port  is  much  wider 
at  the  seat  than  usual.* 

To  clearly  show  the  features  of  novelty  in  this 
valve  over  the  ordinary  slide  valve,  Figs.  158  and 
159  are  given.  The  arrows  in  Fig.  1 58  indicate  the 
double  exhaust  from  the  right-hand  end  of  the 
cylinder  during  the  early  exhaust  period.  In  Fig. 
159  the  arrows  indicate  similarly  the  ordinary 


^Letters  patent  have  been  granted  for  this  valve. 


OPERATION  OF  COMPOUND  LOCOMOTIVES.       1 03 

action  of  an  "Allen"  ported  valve  in  giving  double 
admission  to  the  same  end  of  the  cylinder  during 
the  early  steam  period.  This  style  of  slide  valve 
has  been  in  use  on  locomotives  and  given  only  a 
six-inch  extreme  travel  of  valve  and  has  proven 
very  successful  in  keeping  down  the  back  press- 
ure, especially  at  high  speeds. 


Accidents  to  Richmond  Compounds. — In  case  of 
accident  on  the  road  requiring  the  engine  to  be 
run  in  with  one  cylinder,  what  should  be  done? 
Ordinarily,  open  the  separate  exhaust  or  "emerg- 
ency" valve  and  do  nothing  otherwise  differently 
than  with  a  simple  engine. 

In  case  the  engine  was  running  with  the  low- 
pressure  side  only,  why  do  you  instruct  to  open 
the  separate  exhaust  valve?  So  that  there  shall 
be  no  accumulation  of  pressure  in  the  receiver 
which  might  occur  in  case  of  a  leaky  slide  valve 
or  balance  strips  leaking  on  the  high-pressure 
side. 


104        ENGINEERS'  AND  FIREMEN'S  MANUAL. 

As  the  emergency  port  openings  are  small,  what 
could  be  done  in  order  to  obtain  considerable 
speed  in  case  the  break-down  occurred  in  passen- 
ger service?  Try  to  block  the  slide  valve  on  the 
disabled  side  in  an  extreme  position  so  as  to  un- 
cover the  exhaust  port. 

What  should  be  done  in  case  the  reducing 
valve  stuck  open  or  became  broken?  Care  should 
be  used  in  starting  by  opening  the  throttle  very 


slightly  and  the  engine  should  be  run  as  a  com- 
pound only.  If  it  had  to  be  run  simple,  the 
boiler  pressure  should  be  reduced  about  one-half. 

What  might  cause  the  reducing  valve  to  stick  ? 
Feeding  valve  oil  to  the  low-pressure  side  when 
the  engine  is  working  compound  and  there  is 
consequently  no  flow  of  steam  through  this 
valve. 

What  precaution  would  it  be  advisable  to  ob- 
serve in  case  the  intercepting  valve  became 
broken?  The  engine  should  be  run  compound 


OPERATION  OF  COMPOUND  LOCOMOTIVES.       1 05 

only  and  it  would  be  safer  not  to  stop  with  the 
low-pressure  side  on  center.  If  this  latter  pre- 
caution were  not  observed,  the  high-pressure 
piston  might  have  considerable  back  pressure 
upon  it  from  the  receiver,  should  the  intercepting 
valve  break  in  such  a  way  as  to  permit  live  steam 
from  the  reducing  valve  to  enter  the  receiver  in 
starting. 

What  prevents  slamming  of  the  intercepting 
valve?  The  air  dash-pot  connected  thereto. 

In  this  class  of  compounds,  why  are  the  cylinder 
neads  sometimes  dished,  or  not  flat,  as  is  usually 
the  case?  In  order  to  give  a  maximum  strength 
with  a  minimum  weight  of  piston,  these  builders 
frequently  use  a  piston  such  as  is  shown  in  Fig. 
160;  hence  the  cylinder  heads  conform  to  the 
shape  of  the  piston. 


ROGERS    COMPOUND. 

The  intercepting  valve  originally  employed  by 
the  Rogers  Locomotive  Works  for  their  system  of' 
two-cylinder  compound,  was  placed  in  the  smoke- 
box  and  was  controlled  automatically  and  be- 
yond the  will  of  the  engineer.  In  starting,  by 
placing  the  reverse  lever  in  either  extreme  posi- 
tion, a  separate  reach-rod  with  suitable  levers 
was  made  to  open  the  reducing  valve  and  admit 
live  steam  from  the  boiler  to  the  low-pressure 
cylinder,  and  close  communication  between  the 
latter  and  the  receiver,  so  that  the  high-pressure 
cylinder  exhausted  into  a  closed  reservoir  or  re- 
ceiver. After  one  or  two  strokes  sufficient  pressure 
accumulated  in  the  receiver  to  automatically 
throw  the  intercepting  valve  into  position  for 
working  compound  and  the  hooking  up  of  the 
reverse  lever  closed  the  reducing  valve. 

The  succeeding  arrangement  used  by  these 
builders  is  fully  described  and  illustrated  in  what 
follows.  The  device  is  for  a  two-cylinder  or  cross- 
compound  locomotive,  and  is  placed  in  the  high- 
pressure  saddle  on  the  right  side  and  connected 
to  a  lever  in  the  cab  having  three  notches,  and  is 
operated  by  the  engineer  at  will.  As  long  as 
this  lever  remains  in  the  forward  notch  the  en- 
gine works  as  a  single  expansion  locomotive; 
the  back  notch  places  the  intercepting  valve  in 
compound  position,  while  the  middle  notch 
makes  an  automatic  compound,  that  is,  the  inter- 

(106) 


OPERATION  OF  COMPOUND  LOCOMOTI VES.       107 

cepting  valve  works  the  engine  simple  for  a  few 
strokes  and  then  the  valves  automatically  assume 
the  compound  position.  Thus  this  engine  be- 
longs to  the  class  of  convertible  compounds. 

The  component  parts  of  the  device  are:  A  reg- 
ulating valve  (positively  controlled  by  the  cab 


lever  above  mentioned),  an  intercepting  and  a  re- 
ducing valve  (controlled  either  positively  by  the 
regulating  valve  or  at  times  automatically  by  the 
pressure  in  the  receiver),  and  a  separate  exhaust 
valve  (controlled  by  the  operating  valve).  The 


108 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


OPERATION  OF  COMPOUND  LOCOMOTI VES.        109 


1 1 0         ENGINEERS'  AND  FIREMEN'S  MANUAL. 

intercepting  valve  has  two  positions,  one  for  work- 
ing compound  and  one  for  working  simple.  In 
the  former  position,  as  shown  in  Fig.  163,  the  high- 
pressure  cylinder  exhaust  is  connected  to  the  re- 
ceiver and  thence  to  the  low-pressure  side,  while 
in  the  simple  position,  as  shown  in  Fig.  162,  this 
communication  is  closed  and  the  high-pressure 
exhaust  directed  through  the  separate  exhaust 
valve  to  the  stack,  live  steam  at  the  same  time 
being  admitted  to  the  low-pressure  steam  chest 
through  the  reducing  and  the  intercepting  valves. 

To  somewhat  reduce  the  high  compression  that 
takes  place  in  the  large  low-pressure  cylinder 
when  running  at  high  speeds  without  steam — as, 
for  instance,  down  grades — a  by-pass  arrangement 
similar  in  some  respects  to  "La  Chatalier"  brake  is 
employed.  This  consists  of  an  automatic  device 
for  connecting  the  two  sides  of  the  low-pressure 
piston  when  steam  is  shut  off,  and  will  be  fully 
described  hereafter. 

Fig.  161  is  a  view  from  the  front,  showing  the 
high-pressure  cylinder  to  be  on  the  right-hand 
side  of  the  engine.  In  the  saddle  on  that  side 
are  shown  the  positions  of  the  regulating  valve 
and  the  intercepting  and  separate  exhaust  valves. 
The  location  of  the  by-pass  valve  on  the  low- 
pressure  cylinder  is  also  shown. 

Figs.  162  and  163  are  sectional  views  of  the 
special  valve  mechanism.  For  simplicity  in  ex- 
plaining their  working,  the  regulating  valve  is 
shown  as  though  it  were  located  directly  under- 
neath the  intercepting  valve  which  is  not  its  actual 
position  shown  in  Fig.  161.  The  intercepting 


OPERATION  OF  COMPOUND  LOCOMOTI VE1S.        Ill 

valve  is  composed  of  two  parts  bolted  together 
and  is  shown  cross-sectioned  more  heavily  than 
its  casing  while  the  reducing  valve  L  within  it  is 
distinguishable  by  its  still  darker  appearance.  Its 
principal  port  openings  to  the  receiver  and  from 
the  high-pressure  cylinder  exhaust  are  lettered 
and  the  direction  of  flow  through  them  is  indicated 
by  arrows,  that  an  understanding  may  be  the  more 
easily  arrived  at.  Port  G  is  an  annular  chamber 
around  the  intercepting  valve  cylinder  H  and  is 
connected  with  the  high-pressure  steam  pipe  in  the 
saddle  and  therefore  has  live  steam  pressure  when 
the  engine  throttle  is  open.  Between  G  and  the  in- 
tercepting valve  is  a  series  of  holes  marked  J. 
The  intercepting  valve  is  hollow  and  has  two  se- 
ries of  holes  through  its  shell  at  P  and  Q,  the 
latter  being  to  the  right  of  the  reducing  valve  seat. 
Fig.  162  shows  the  intercepting  valve  closed  (to 
the  right)  on  its  seat  A,  and  the  reducing  valve 
off  its  seat  (open),  as  it  is  when  working  simple 
except  that  the  reducing  valve  L  is  then  brought 
near  enough  to  its  seat  to  the  left,  to  prevent 
more  than  about  one-half  the  boiler  pressure  from 
passing  through  it.  As  usual,  the  reducing  is 
accomplished  by  the  two  ends  of  the  reducing 
valve  L  being  of  different  diameters,  the  smaller 
end  having  its  outer  left-hand  side  always  con- 
nected to  the  atmosphere  through  small  ports 
marked  N  and  0;  while  the  outside  of  the  larger 
right-hand  end  is  exposed  to  the  receiver  press- 
ure when  in  operation,  as  in  Fig.  162.  The  left- 
hand  smaller  end  M  of  the  intercepting  valve 
works  in  a  cylinder  W,  while  the  right-hand 


112         ENGINEERS'  AND  FIREMEN'S  MANUAL. 

larger  area  of  the  intercepting  valve  is  exposed 
either  to  the  receiver  or  the  high-pressure  exhaust 
cavity,  according  to  the  position  of  the  valve. 
The  separate  exhaust  valve  is  located  in  a  cham- 
ber U  directly  connected  to  the  main  exhaust 
pipe  Z.  (See  Figs.  161  and  163.)  The  right- 
hand  end  of  the  separate  exhaust  valve  is  in  the 
form  of  a  piston  and  works  in  a  cylinder  T.  The 
outer  ends  of  these  two  cylinders,  W  and  T,  are 
connected  by  small  pipes  C  and  D  with  the  regu- 
lating valve,  as  shown  in  Figs.  162  and  163.  The 
stem  of  the  intercepting  valve  extends  over  into 
separate  exhaust  valve  and  forms  a  guide  to 
keep  both  valves  central,  and  also  serves  as  a 
dash-pot,  but  allows  each  valve  to  act  independ- 
ently of  the  other.  All  pistons  are  fitted  with 
packing  rings,  as  shown,  and  the  valve  seats  and 
ground  joints  are  so  indicated. 

The  regulating  valve  receives  steam  from  G 
through  a  small  port  X  and  therefore  has  live 
steam  whenever  the  engine  throttle  is  open.  The 
regulating  valve  consists  of  a  slide  valve  of  the 
well-known  "D"  type  and  moves  on  a  seat  having 
two  steam  ports  and  one  exhaust  opening,  as 
usual  with  a  slide  valve.  Steam  admitted  through 
the  right  steam  port  and  pipes  DD  to  chamber  T 
would  bear  against  the  separate  exhaust  valve  and 
close  it,  as  in  Fig.  163.  Steam  through  the  left 
port  and  pipes  CC  to  chamber  W  would  force  the 
intercepting  closed,  as  in  Fig.  162.  If  the  engi- 
neer places  the  regulating  valve  lever  in  the 
forward  notch,  as  in  Fig.  162,  live  steam  entering 
the  regulating  valve  chamber  from  ports  G  and  X 


OP  K 11  AT  ION  OF  COMPOUND  LOCOMOTI  VEX.       1 13 

finds  the  left  hand  port  uncovered  and  passes 
through  the  small  pipe  CC  to  the  cylinder  W  (as 
indicated  by  arrows),  moving  the  intercepting 
valve  to  the  right  against  its  seat  A  and  thereby 
closing  communication  between  the  high-pressure 
cylinder  exhaust  port  and  the  receiver  R.  In 
this  position  live  steam  pressure  from  G  passes 
through  ports  JJ  and  PP  to  the  interior  of  the 
intercepting  valve,  automatically  opening  the 
reducing  valve  and  flowing  through  ports  QQ, 
enters  the  receiver  jR,  the  other  end  of  which 
is  connected  to  the  low-pressure  steam  chest, 
as  shown  in  Fig.  161.  Thus  the  low-pressure 
cylinder  has  received  live  steam  at  a  reduced 
pressure  and  can  work  independently  of  the  high- 
pressure  cylinder,  as  its  exhaust  is  as  always  to 
the  stack.  The  intercepting  valve  now  being- 
closed,  the  exhaust  from  the  high-pressure  cyl- 
inder (its  communication  to  the  receiver  being 
thereby  shut  off)  forces  the  separate  exhaust  valve 
off  its  seat,  as  in  Fig.  162,  and  escapes  to  the  stack 
and  the  engine  works  simple,  or  with  a  live 
steam  admission  and  an  exhaust  to  the  atmos- 
phere on  both  sides.  The  separate  exhaust  valve 
remains  open,  as  shown  in  Fig.  162,  because 
chamber  T  is  connected  to  the  atmosphere 
through  pipe  DD,  the  under  side  of  the  regulat- 
ing slide  valve,  and  pipe  E — as  indicated  by  ar- 
rows. 

If  the  regulating  lever  in  the  cab  be  moved  to 
the  back  notch,  the  regulating  valve  takes  the 
position  shown  in  Fig.  163  and  will  then  admit 
steam  through  the  right-hand  pipe  DD,  into 


1  1  4         ENGINEERS'  AND  FIREMEN'S  MANUAL. 

chamber  T,  pushing  and  holding  the  separate  ex- 
haust valve  against  its  seat  B,  and  at  the  same 
time  chamber  Trwill  be  in  exhaust  through  pipes 
CC  and  E,  as  indicated  by  arrows.  The  separate 
exhaust  valve  being  now  closed,  a  slight  pressure 
in  the  cavity  marked  '  'high-pressure  cylinder 
exhaust"  will  open  the  intercepting  valve,  that  is, 
move  it  off  its  seat  A  into  the  position  shown  in 
Fig.  163.  Then  the  high-pressure  cylinder  ex- 
hausts through  the  intercepting  valve  into  the 
receiver  and  thence  to  the  low-pressure  steam 


Compound 


fosifton 


chest,  and  the  engine  works  compound.  No  live 
steam  from  ports  GG  can  get  to  the  receiver  in 
this  position  as  the  ports  PP  are  not  in  register 
with  those  at  JJ. 

It  will  be  noticed  that  there  is  an  extended  flange 
on  the  face  of  the  intercepting  valve,  that  enters  the 
seat  of  the  latter  enough  before  closing  and  leaves 
it  sufficiently  late  in  opening,  to  prevent  live 
steam  from  flowing  through  ports  PP,  QQ,  and  R 
to  the  high-pressure  cylinder  exhaust  port  when 


OPERATION  OF  COMPOUND  LOCOMOTI  YES.       115 

the  intercepting  valve  is  opening  or  closing.  If 
the  engine  is  standing  and  the  regulating  valve 
is  moved  to  its  central  position,  as  shown  in  Fig. 
164,  when  the  throttle  is  opened  steam  will  pass 
through  both  pipes  CC  and  DD  to  the  outer  ends 
of  the  intercepting  and  the  separate  exhaust  valves 
respectively,  and  they  will  both  be  instantly 
closed  against  their  respective  seats  A  and  B, 
Figs.  162  and  163.  The  receiver  would  then  be 
filled  with  steam  through  the  hollow  intercepting 
valve  and  the  reducing  valve,  as  indicated  by  the 
arrows  in  Fig.  1 62 ;  but  as  soon  as  the  pressure  at  the 
high-pressure  exhaust  port  became  about  twenty 
per  cent,  of  the  pressure  in  the  dry  pipe  at  the 
time,  the  intercepting  valve  would  be  opened  and 
thereafter  held  open  by  the  receiver  pressure  act- 
ing toward  the  left  on  the  large  right-hand  end 
of  the  intercepting  valve;  thus  a  slight  pressure 
on  the  large  area  of  this  valve  overbalances  the 
higher  pressure  on  the  smaller  left-hand  end  M 
in  chamber  W,  and  the  engine  automatically 
changes  to  compound  after  two  or  three  strokes, 
the  main  ports  being  opened  as  in  Fig.  163. 

If  the  engine  had  been  working  simple,  with  the 
valves  as  in  Fig.  162,  and  the  operating  valve  lever 
were  placed  in  either  the  center  or  back  notch, 
the  working  would  automatically  be  changed  to 
compound;  if  in  the  center  notch,  it  would  take  a 
slight  accumulation  of  pressure  at  the  high-press- 
ure exhaust  port,  as  just  explained;  if  in  the  back 
notch  the  intercepting  valve  opens  with  almost  no 
pressure  from  the  high-pressure  exhaust  port  as 
then  chamber  IF  is  in  exhaust  through  pipe  CC 


116 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


and  the  regulating  valve.  Subsequently  to  work- 
ing simple,  it  is  best  to  move  the  regulating  lever 
to  its  middle  position  (Fig.  164)  for  a  few  sec- 
onds without  closing  the  engine  throttle;  after 
that  it  can  be  moved  to  its  back  notch,  as  in  Fig. 
163,  and  left  there  until  it  is  desired  to  again 
start  simple  or  go  from  compound  to  single-ex- 


.  /66. 


r=^. — r — 


CyZ.JP0rt 


pansion  in  order  to  prevent  stalling  on  a  heavy 
grade. 

Figs.  165  and  166  show  two  views  of  the  by- 
pass arrangement  which  is  placed  on  the  low-press- 
ure cylinder  in  the  position  shown  in  Fig.  161. 
It  consists  of  a  valve  F which  automatically  opens 


OPERATION  OF  COMPOUND  LOGOMOTI VES.       117 

and  closes  the  port  in  a  hollow  casting  bolted  to 
the  cylinder  and  connected  below  the  valve  seat 
at  K  and  L  with  the  steam  ports  of  the  low-press- 
ure cylinder,  as  illustrated  in  Figs.  165  and  166. 
The  hole  through  this  by-pass  casting  is  two 
inches  in  diameter.  In  Fig.  166  the  valve  Fis 
shown  dropped  down  in  its  chamber,  thus  leaving 
a  two-inch  open  communication  between  the 
steam  ports  and  hence  the  two  sides  of  the  low- 
pressure  piston.  A  small  pipe  from  the  live  steam 
port  in  the  saddle  of  the  high-pressure  cylinder 
leads  through  the  pipe  S  to  the  under  side  of  this 
cylindrical  valve  F,  as  shown,  so  that  when  the 
engine  throttle  is  opened  the  valve  Fraisestothe 
top  of  its  chamber  and  shuts  off  all  communica- 
tion between  the  ports  K  and  L,  remaining  there 
as  long  as  the  high-pressure  cylinder  is  receiving 
steam;  but  when  the  throttle  is  closed,  it  falls 
again  by  gravity  and  is  thus  an  automatic  valve. 

Accidents  to  Rogers7  Compounds. — In  case  of 
break-down  on  one  side  of  this  engine,  can 
it  be  run  in  with  the  other  side?  Yes.  The 
reducing  valve  would  furnish  a  live  steam 
supply  for  the  low-pressure  cylinder,  or  the  sep- 
arate exhaust  valve  would  give  an  exhaust  open- 
ing for  the  use  of  the  high-pressure  cylinder, 
according  to  which  side  was  to  be  used;  hence,  in 
either  case,  general  instructions  would  be  to  place 
the  regulating  valve  in  its  extreme  forward  posi- 
tion, as  for  working  simple,  Fig.  162. 

Under  such  circumstances  would  the  engine 
be  as  powerful  as  a  simple  engine  on  one  side? 
Yes,  considerably  more  so  at  low  speed,  but  the 


1 1 8        ENGINEERS'  AND   'FIREMEN'S  MANUAL. 

smaller  port  openings  than  usual  would  not  per- 
mit of  as  great  speed. 

As  there  are  three  notches  in  the  cab  for  the 
regulating  valve  lever,  how  should  this  be  handled 
when  it  is  desired  to  change  from  simple  to  com- 
pound, or  the  reverse?  It  is  not  advisable  to 
throw  it  from  forward  to  back  notch,  or  the  oppo- 
site, without  pausing  a  second  or  two  in  the  mid- 
dle notch  and  thereby  producing  a  more  gradual 
movement  and  causing  a  cushioning  of  the  in- 
tercepting and  separate  exhaust  valves. 

Under  ordinary  circumstances,  in  what  posi- 
tion is  it  best  to  keep  the  regulating  valve?  In 
the  back  notch,  or  compound  position. 

How  should  a  light  train  be  started?  With 
the  regulating  valve  lever  in  the  center  notch. 
The  engine  starts  thus  as  an  automatic  com- 
pound. 

If  the  engine  actually  works  compound  in  the 
center  position,  why  is  that  not  advisable?  Be- 
cause in  that  position  the  opening  and  closing  of 
the  throttle  while  running  and  the  wide  varia- 
tions of  pressure  in  the  steam  pipe  and  receiver 
when  running,  would  cause  more  or  less  unneces- 
sary movements  of  the  intercepting  valve. 

When  running  the  engine  with  one  side,  in 
what  position  will  the  "by-pass"  valves  (Figs. 
165  and  166)  be  found?  No  matter  which  side 
is  in  use,  live  steam  from  the  high-pressure 
steam  pipe  acts  to  keep  them  closed. 

What  kind  of  oil  should  be  used  in  the  oil 
cups  shown  in  Fig.  162?  Nothing  but  valve  oil 
and  that  regularly  but  not  too  often,  as  it  has  a 


OPERATION  OF  COMPOUND  LOCOMOTI VES.       1 1 9 

tendency  to  gum  the  valves  where  there  is  not  a 
constant  flow  of  steam. 

If  the  high-pressure  side  were  on  the  center, 
why  would  not  the  engine  move  with  the  operat- 
ing lever  in  compound  position  (back  notch)? 
Because  then  the  valves  would  be  as  in  Fig.  163 
and  no  live  steam  could  be  admitted  to  the  low- 


pressure  cylinder.  This  would  not  be  the  case  in 
starting  with  the  regulating  lever  in  either  of 
the  other  two  notches. 

BROOKS    TWO-CYLINDER    COMPOUND. 

This  design  is  of  the  two-cylinder  or  cross-com- 
pound type,  built  under  the  Player  patents,  having 


120         ENGINEERS'  AND  FIREMEN'*  MANUAL. 

the  high-pressure  cylinder  on  the  left  side  and  a 
receiver  in  the  smoke-box  between  the  two  cylin- 
ders, as  shown  in  Fig.  167. 

There  is  a  combined  admission,  pressure-regu- 
lating and  intercepting  valve  located  either  on 
the  receiver  in  the  smoke-box  as  shown,  or  in  the 
cylinder  saddle,  which  valve  upon  opening  the 
engine  throttle  admits  live  steam  at  a  reduced 
pressure  to  the  low-pressure  cylinder;  at  the  same 
time  the  intercepting  valve  automatically  closes, 
preventing  the  live-steam  pressure  from  working 
against  the  high-pressure  piston.  The  reducing 
valve  remains  open  until  the  pressure  in  the  re- 
ceiver, accumulating  from  the  high-pressure  ex- 
haust, becomes  equal  to  or  slightly  greater  than 
that  on  the  low-pressure  side,  when  the  valve 
automatically  closes,  thereby  shutting  off  the  ad- 
mission of  live  steam,  and  the  intercepting  valve 
simultaneously  opens  the  receiver  to  the  low- 
pressure  steam  chest,  and  the  engine  works  com- 
pound thereafter  as  long  as  the  throttle  remains 
open. 

In  order  to  give  the  engineer  control  of  the 
locomotive  at  all  times,  controlling  valves  are 
provided  on  the  low  pressure  side.  In  the  illus- 
tration (Fig.  168)  these  valves,  A  and  B,  are  shown 
located  in  the  bottom  of  the  receiver  and  are  con- 
nected to  the  cab  by  suitable  levers  C  and  D. 
They  are  sometimes  made  larger,  connected 
higher  up  with  the  exhaust  pipe,  and  arranged 
as  to  work  automatically  in  combination  with  the 
intercepting  valve,  so  that  the  engine  can  be  run 
simple  as  long  as  desired  and  the  exhaust  take 


OPERATION  OF  COMPOUND  LOCOMOTI VES.       121 


TWQ-CYLJNDER  COMPOUND, 


122 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


place  through  the  stack;  however,  its  builders 
have  claimed  the  design  here  shown  to  be  "all  that 
is  necessary  to  give  the  engine  its  maximum 
power." 

The  operation  of  the  locomotive  is  as  follows: 
When  the  engine  throttle  is  opened,  live  steam  is 


admitted  to  the  high-pressure  steam  chest  through 
the  steam  pipe  8  (Figs.  167  and  168)  and  op- 
erates upon  the  high-pressure  piston  in  the  usual 
manner.  At  the  same  time,  through  the  small 
steam  pipe  L,  steam  acts  against  the  seat  E  of 
the  reducing  valve,  then  closed  as  in  Fig.  170, 


OPERATION  OF  COMPOUND  LOCOMOTI  VEti.       123 

causing  this  valve  to  open,  passing  through  the 
hollow  portion  of  the  valve,  automatically  clos- 
ing the  intercepting  valve  against  its  seat  F  on 
the  receiver,  as  in  Fig.  169.  Steam  then  flows 
through  the  passages  in  the  intercepting  valve 
and  down  to  the  low-pressure  steam  chest,  as  in- 


C&sed, 


dicated  by  the  arrows.  To  render  them  readily 
distinguishable,  the  reducing  or  regulating  valve 
is  cross-sectioned  very  heavily,  while  the  inter- 
cepting valve  is  less  dark  in  appearance. 

From  Figs.  169  and  170,  it  will  be  seen  that 
the  right-hand  end  of  the  reducing  valve  is  of 
larger  area  than  that  acted  upon  by  live  steam  at 


1 24         ENGINEERS'  AND  FIREMEN'S  MANUAL. 

its  seat  on  the  left-hand  end  E.  It  is  this  dif- 
ference that  causes  the  partial  closing  of  the 
valve,  thereby  throttling  the  steam  passing 
through  it  to  a  reduced  pressure.  These  areas 
being  about  two  to  one,  the  reducing  valve,  in 
order  to  equalize  the  work  of  the  two  cylinders 
in  starting,  prevents  more  than  about  one-half 
the  pressure  in  the  dry  pipe  from  passing  to  the 
low-pressure  cylinder. 

As  soon  as  the  high -pressure  cylinder  has  ex- 
hausted sufficient  steam  into  the  receiver  to 
overbalance  the  reduced  live  steam  pressure 
holding  the  intercepting  valve  closed,  this  valve 
opens  automatically,  at  the  same  time  locking  the 
regulating  valve  against  its  seat  as  shown  in  Fig. 
1 70.  Exhaust  steam  from  the  high-pressure  cyl- 
inder then  flows  through  the  receiver  to  the  low- 
pressure  steam  chest,  as  indicated  by  the  arrows 
and  the  engine  works  compound.  The  receiver 
pressure  can  become  considerably  reduced  and 
still,  through  the  action  of  the  combined  valves, 
keep  the  pressure  regulating  valve  closed. 

Accidents  to  Brooks  Two-Cylinder  Compounds.— 
What  should  be  done  in  case  of  an  accident 
necessitating  the  removal  of  the  main  rod  on  the 
low-pressure  side?  Disconnect  that  side,  block 
the  crosshead  and  clamp  the  valve  in  center,  as 
with  a  simple  engine.  Open  wide  the  control- 
ling valves  underneath  the  saddle  and  run  in  with 
one  side.  The  exhaust  will  take  place  through 
these  valves.  To  obtain  a  larger  exhaust  opening 
than  the  controlling  valves  furnish  and  thus  per- 
mit of  more  speed  and  better  steaming  qualities, 


OPERATION  OF  COMPOUND  LOCOMOTIVES.    '    125 

attempt  should  be  made  to  place  the  slide  valve 
on  the  disabled  side  so  as  to  uncover  the  exhaust 
port  and  thus  give  an  exhaust  through  the  stack. 

What  should  be  done  for  a  similar  accident 
to  the  high-pressure  side?  Just  the  same  as  for 
a  simple  engine.  There  being  then  no  exhaust 
into  the  receiver,  the  intercepting  and  reducing 
valve  would  admit  live  steam  to  the  low-press- 
ure cylinder  upon  opening  the  engine  throttle. 

What  mode  of  procedure  should  be  followed  in 
case  of  a  broken  valve  stem  or  rocker  arm?  Pro- 
ceed as  above,  according  to  which  side  was  broken. 

What  should  be  done  if  the  intercepting 
valve  became  broken  so  as  to  leave  an  open- 
ing between  both  ends  of  the  receiver?  The 
proper  method  would  be  to  disconnect  the  small 
steam  pipe  L  (Figs.  167  and  168)  and  insert  a 
blind  gasket.  The  engine  could  then  be  started 
and  worked  only  as  a  "strictly  plain"  compound 
and  should  not  be  stopped  with  the  high-pressure 
side  on  center,  as  no  live  steam  could  be  given 
the  low-pressure  cylinder  for  starting.  Without 
disconnecting  the  steam  pipe  the  engine  could  be 
run  in  with  part  of  a  train  by  reducing  the  boiler 
pressure  or  by  using  a  slightly  open  throttle,  in 
which  case  live  steam  from  the  reducing  valve 
would  pass  through  the  receiver  and  work  against 
the  high-pressure  piston  in  starting,  and  hence 
the  engine  should  not  then  be  stopped  with  the 
low-pressure  side  on  center. 

What  should  be  done  for  a  broken  reducing 
yalve?  The  same  as  for  a  broken  intercepting 
valve, 


126         ENGINEERS'  AND  FIREMEN'S  MANUAL. 

Should  the  controlling  valves  fail  to  open, 
where  would  you  look  for  the  cause  of  the  trouble  ? 
They  operate  very  similarly  to  cylinder  cocks  and 
their  levers  becoming  disconnected  or  bent  may 
cause  them  to  either  fail  to  open,  or  remain  con- 
tinually open,  as  the  case  may  be.  The  remedy 
is  obvious. 

BROOKS    FOUR-CYLINDER    TANDEM    COMPOUND. 

The  Brooks  (Player  System)  of  four-cylinder 
compound  is  of  the  tandem  type,  that  is,  two 
cylinders  on  each  side,  one  ahead  of  the  other,  as 
shown  in  Fig.  109.  With  this  system  the  two 
low-pressure  cylinders  and  their  saddles  are  placed 
similarly  to  ordinary  single-expansion  cylinders, 
with  which  they  can  always  be  made  inter- 
changeable. They  are  of  course  larger,  have  a 
different  style  of  steam  chest  and,  bolted  prefer- 
ably to  their  forward  ends,  as  shown  in  Figs.  109 
and  171,  are  the  two  high-pressure  cylinders 
which  have  steam  chests  communicating  with 
the  steam  chests  of  the  low-pressure  cylinders 
with  an  enlargement  between,  all  together  form- 
ing a  receiver.  There  are  no  devices  in  the 
smoke-box  except  those  usual  to  single-expan- 
sion locomotives. 

The  steam  is  supplied  to  the  high-pressure 
valve  chest  through  suitable  pipes  connecting 
with  the  usual  steam  pipes  in  the  smoke-box,  and 
the  exhaust  from  the  low-pressure  cylinder  is 
through  the  usual  cavity  in  the  saddle. 

As  shown  in  Fig.  171,  the  low-pressure  cylin- 
ders are  fitted  with  the  usual  balanced  slide 


OPERATION  OF  COMPOUND  LOCOMOTIVES        127 

valves,  while  the  valves  for  the  high-pressure  cyl- 
inders are  of  the  piston  type  and  hollow,  having 
internal  admission  and  external  exhaust  edges. 
The  low-pressure  valve  is  controlled  by  the  usual 
eccentric  and  rocker  arms,  as  ordinary  with  simple 
engines'.  It  is  rendered  advisable  to  have  an  in- 
ternal admission  with  the  high-pressure  valve  in 
order  to  lessen  the  cooling  of  the  steam  from  the 
boiler  as  well  as  for  constructive  reasons. 

On  account  of  the  high-pressure  valve  having 
internal  admission  and  the  low-pressure  valve 
having  external  admission  (the  latter  being 
usual  with  ordinary  slide  valves)  it  is  necessary 
that  these  valves  should  travel  in  opposite  direc- 
tions. This  is  accomplished  by  placing  in  the 
receiver  (as  shown  in  Fig.  171)  an  intermediate 
rocker  arm  A  which  is  connected  by  rods  to  both 
valves  and  has  arms  of  the  desired  ratio  to  give 
a  relatively  less  travel  to  the  high  than  to  the 
low-pressure  valve.  These  valves  are  so  propor- 
tioned that  when  running  in  nearly  full  gear,  the 
high-pressure  cut-off  takes  place  later  in  the 
stroke  than  the  low-pressure  cut-off,  but  when  the 
engine  is  hooked  up  the  relative  time  of  cut-offs 
changes. 

The  pistons  of  both  the  high  and  the  low- 
pressure  cylinder  are  fitted  upon  the  same  piston 
rod,  the  intermediate  head  between  the  two 
cylinders  having  suitable  metallic  packing,  as 
shown  in  the  illustration. 

On  the  low-pressure  steam  chest  is  fitted  a  re- 
ducing and  starting  valve  which  is  connected  with 
the  high-pressure  steam  pipe,  as  shown  with  the 


128        ENGINEERS'  AND  FIREMEN'S  MANUAL. 


<3 


I 


S 


OPERATION  OF  COMPOUND  LOCOMOTIVES.       129 

reducing  valve  in  closed  position  by  Fig.  172. 
By  the  connection  of  a  rod  with  the  arm  of  the 
lift  shaft,  this  reducing  valve  is  automatically 
opened  whenever  the  reverse  lever  is  placed 
either  in  full  forward  or  full  back  gear.  In  the 
intermediate  positions  of  the  reverse  lever,  this 
reducing  valve  is  locked  to  its  seat  by  a  suitable 
spring,  so  that  it  is  rendered  inoperative  and  the 
engine  must  necessarily  work  compound  at  all 

&*  /72 


times  and  under  all  conditions  of  steam  pressure 
when  the  reverse  lever  is  in  any  other  position 
than  full  gear.  Fig.  172  shows  the  range  of  the 
lift  shaft  arm  for  the  starting  valve  to  be  either 
open  or  closed.  This  combined  starting  and  re- 
ducing valve,  when  open,  permits  live  steam  to 
enter  the  low-pressure  cylinder  at  a  pressure 
equivalent  to  the  maximum  pressure  obtained  in 


130        ENGINEERS'  AND  FIREMEN'S  MANUA  L. 

this  cylinder  when  the  engine  is  working  com- 
pound. As  soon  as  the  engine  has  made  one 
complete  revolution,  the  receiver  becomes  charged 
sufficiently  by  the  exhaust  from  the  high-pressure 
cylinder  to  close  the  reducing  valve  against  its 
spring,  thus  automatically  rendering  the  starting 


valve  inoperative  and  thereby  necessitates  the 
compound  working  of  the  engine.  The  reducing 
valve  on  a  larger  scale  is  shown  in  open  or  start- 
ing position  by  Fig.  173. 

The  engine  operates  in  the  following  manner: 
Steam  is  admitted   to   the   high-pressure  steam 


OPERATION  OF  COMPOUND  LOCOMOTIVES.       131 

chest  through  suitable  pipes,  into  the  annular 
steam  admission  cavity  surrounding  the  high- 
pressure  piston  valve,  thence  to  the  high-pressure 
cylinder,  and  exhausts  into  the  receiver — the  ex- 
haust from  the  forward  end  of  the  cylinder  pass- 
ing through  the  inside  of  the  hollow  piston  valve. 
The  low-pressure  steam  chest,  being  also  of  large 
size,  somewhat  increases  the  receiver  capacity,  so 
that  practically  uniform  pressure  is  maintained 
therein,  steam  from  the  receiver  being  admitted 
to  and  exhausted  from  the  low-pressure  cylinder 
by  an  ordinary  slide  valve  which  gives  a  dis- 
tribution in  that  cylinder  in  the  same  manner  as 
for  simple  engines. 

This  style  of  compound  has  been  in  operation 
for  several  years  and,  the  builders  state,  shows  an 
excellent  economy  in  fuel,  water,  and  repairs. 

Accidents  to  Brooks  Four-Cylinder  Tandem  Com- 
pound.— What  would  you  do  if  it  became  neces- 
sary to  disconnect  one  side  of  the  engine?  The 
same  as  with  a  simple  engine  of  similar  design- 
in  other  respects. 

In  case  the  front  head  of  the  high-pressure 
cylinder  became  broken,  how  would  you  proceed 
in  order  to  run  the  engine  in  with  a  full  train? 
Remove  the  front  steam  chest  head,  place  the 
reverse  lever  so  as  to  throw  the  high-pressure 
valve  clear  ahead,  disconnect  the  high-pressure 
valve  and  its  intermediate  rocker-arm  rod  (Fig. 
171)  and  block  this  valve  securely  in  the  center 
so  as  to  cover  all  ports;  then  block  the  starting 
valve  open  on  that  side,  thereby  allowing  live 
steam  at  a  reduced  pressure  to  enter  the  low- 


132         ENGINEERS'  AND  FIREMEN'*  MANUAL. 

pressure  cylinder.  This  will  enable  the  engineer 
to  slowly  handle  a  full  train,  but  should  not  be 
so  run  for  any  distance  or  the  high-pressure  cyl- 
inder will  be  badly  cut.  In  the  lighter  service  of 
passenger  trains,  the  engine  would  be  capable  of 
greater  speed  by  disconnecting  the  broken  side, 
blocking  the  valves  in  the  center  of  their  seats, 
and  running  with  one  side,  as  would  be  done  with 
a  simple  engine. 

If  the  intermediate  rocker  arm  or  the  valve  rod 
should  break  what  should  be  done?  Broken  at 
some  certain  points,  the  engine  might  be  treated 
as  for  broken  high-pressure  cylinder  head;  but 
the  preferable  procedure,  all  things  considered, 
would  be  to  disconnect  on  that  side  and  be  sure 
to  block  both  valves  over  ports,  to  do  which  it 
may  be  necessary  to  remove  front  steam  chest 
head  and  block  the  high-pressure  valve  inside. 

In  disconnecting  one  side  of  these  engines, 
should  it  be  imperative  to  securely  block  the 
crosshead?  It  should,  because  of  the  difficulty 
of  securely  holding  the  high-pressure  valve  in  its 
central  position. 

How  could  it  be  determined  if  the  metallic 
piston-rod  packing  between  the  two  cylinders 
were  blowing  badly?  Place  the  engine  with  one 
side  on  the  upper  quarter  and  the  reverse  lever 
in  the  center,  block  open  the  starting  valves,  and 
open  the  cylinder  cocks  and  the  throttle.  If  no 
steam  escapes  from  either  the  high  or  low-press- 
ure cylinder  cocks,  it  has  been  determined  that 
the  valves  are  not  leaking.  Now  close  the 
throttle  and  remove  blocks  from  reducing  valve, 


OPERATION  OF  COMPOUND  LOCOMOTIVES,       1 33 

put  the  reverse  lever  in  about  half  forward  gear 
and  allow  all  steam  previously  admitted  to  the 
pipes  to  escape  from  the  open  cylinder  cocks. 
Again  open  the  throttle  and,  as  steam  will  then 
be  admitted  behind  the  high-pressure  piston  only, 
a  blow  through  the  forward  low-pressure  cylinder 
cock  would  indicate  that  this  packing  was  blowing. 
The  same  operation  should  be  repeated  for  test- 
ing the  other  side. 

Should  the  engine  fail  to  develop  its  proper 
starting  power  in  full  gear,  what  might  be  wrong? 
Open  the  cylinder  cocks,  with  the  throttle  open 
and  the  engine  standing,  and  if  steam  at  no  con- 
siderable pressure  escapes  from  the  low-pressure 
cylinder,  examine  the  attachments  connecting  the 
reverse  lever  with  the  starting  valves;  they  oper- 
ate similarly  to  the  ordinary  cylinder  cock  ar- 
rangement and  may  likewise  become  defective 
and  thus  fail  to  open  the  reducing  valve. 


COOKE   COMPOUND. 


The  compound  arrangement  for  two-cylinder 
locomotives  built  by  the  Cooke  Locomotive 
Works  is  such  that,  by  means  of  a  small  steam 


FIG.  174.    COOKE  COMPOUND. 

operating  valve  in  the  cab,  the  engine  can  be 
run  either  simple  or  compound  as  the  engineer 
may  desire,  and  is,  therefore,  a  convertible  com- 
pound. This  operating  valve  admits  steam  to 
suitable  pistons  which  open  and  close  the  inter- 

(134) 


OPERATION  OF  COMPOUND  LOCOMOTIVE*.       1 35 

cepting  valve  and  operate  the  reducing  valve  by 
a  suitable  lever  connection.  The  intercepting 
valve  is  placed  on  the  right-hand  side  of  the  en- 
gine within  the  saddle  of  the  low-pressure  cyl- 
inder and  in  the  passages  JS1?,  leading  from  the 
receiver  to  the  low-pressure  cylinder,  as  shown 
in  Fig.  174;  it  also  has  two  connecting  ports  AA, 
leading  into  the  main  exhaust  to  the  stack.  By 
the  movement  of  this  valve,  steam  from  the  high- 
pressure  cylinder,  coming  through  the  receiver, 
can  be  thrown  out  to  the  atmosphere  instead 
of  being  allowed  to  pass  to  the  low-pressure  cyl- 


Fiy.175. 


inder  for  compound  expansion.  This  movement 
makes  an  independent  engine  of  the  high-press- 
ure side  and  at  the  same  time  opens  a  reducing 
valve  D,  Fig.  174,  which  supplies,  at  a  reduced 
pressure,  live  steam  from  the  boiler  to  the  low- 
pressure  steam  chest.  The  high-pressure  cylinder 
always  exhausts  into  the  receiver,  and  the  ex- 
haust from  the  low-pressure  cylinder  is  direct  to 
the  stack  with  either  simple  or  compound 
working. 

The  reader  will  notice  a  novelty  in  the  shape 


136 


ENGINEERS'  AND  FTREWEN'*  MANUAL. 


of  an  additional  low-pressure  cut-off  lever  G, 
located  in  the  cab,  as  shown  in  Fig.  174.  This 
lever  is  sometimes  applied  to  Cooke  engines  of 
this  class  and  is  used  to  increase  or  decrease  the 
travel  of  the  slide  valve  on  the  low-pressure  side 
independently  of  the  valve  on  the  high-pressure 
side,  in  order  to  equalize  the  power  developed  on 
opposite  sides  of  the  engine  under  variable  con- 
ditions of  steam  pressure  and  different  positions 
of  the  reverse  lever. 


/77 


The  intercepting  valve  is  composed  of  two 
pistons  in  duplicate,  as  shown  in  Figs.  174,  177 
and  178,  each  part  being  moved  by  a  piston  F  in  a 
separate  chamber.  Figs.  175  and  176  show  one- 
half  of  the  valve  removed  from  its  chamber.  It 
will  readily  be  seen  from  Fig.  174,  that  live 
steam  from  the  engineer's  valve  V  in  the  cab  can 
be  supplied  through  two  small  pipes  S  and  C  to 
either  the  outer  or  the  inner  sides,  respectively, 
of  these  two  pistons  FF.  Ports  ER  are  passages 


OPERATION  OF  COMPOUND  LOCOMOTIVES.       1 37 

from  the  receiver  and  ports  EE  lead  to  the  low- 
pressure  steam  chest. 

To  start  the  engine  with  single  expansion  or 
to  run  it  thus  at  any  time,  the  engineer  pulls  the 
handle  of  his  engineer's  valve  V  in  the  cab  to  the 
back  notch.  This  admits  live  steam  through  the 
small  pipe  S  (Fig.  174)  to  outside  ends  of  the  two 
pistons  FI\  thereby  moving  them  and  their  at- 
tached intercepting  valve  pistons  until  the  two 
latter  come  together,  the  position  in  which  they 


are  shown  on  a  larger  scale  in  Fig.  177.  In  this 
position  the  intercepting  valve  has  closed  the 
ports  EE  to  the  low-pressure  cylinder,  and  the 
high-pressure  exhaust  into  the  receiver  can  pass 
out  from  ports  RR,  through  the  hollow  intercept- 
ing valves  and  escape  to  the  atmosphere  by 
exhaust  ports  A  A  leading  to  the  main  exhaust,  as 
indicated  by  arrows.  The  extended  and  slotted  stem 
of  the  left-hand  intercepting  valve  piston  JF(  shown 
in  Figs.  174  and  175)  in  moving  to  the  right  has 


1 38         ENGINEERS'  AND  FIREMEN^  MANUAL. 

pulled  with  it  the  crank  lever  J^(Fig.  174)  and 
opened  the  reducing  valve  1)  which,  by  a  con- 
necting pipe  tapped  into  the  main  steam  passage 
of  the  high-pressure  side,  admits  live  steam  to 
the  low-pressure  steam  chest  through  pipe  J. 

When  the  engineer  desires  to  work  compound, 
he  pushes  the  handle  of  the  engineer's  valve  Fin 
the  cab  to  the  forward  notch,  thereby  admitting 
steam  through  pipe  C  (Fig.  174)  to  the  inner 
sides  of  the  two  intercepting  valve  pistons  FF 
and  forcing  them  and  their  valves  outward,  as 
shown  in  Fig.  178.  In  this  position  the  passage 
is  opened  from  -the  receiver  through  the  inter- 
cepting valve  ports  EE  and  EE  to  the  low- 
pressure  steam  chest  (See  Fig.  174).  The  out- 
ward movement  of  the  pistons  FF  has  shut  off  the 
admission  of  live  steam  to  the  low-pressure  cyl- 
inder by  closing  the  reducing  valve  D,  and  the 
steam  must  now  pass  from  the  high-pressure  cylin- 
der through  the  receiver  and  the  low-pressure  cyl- 
inder to  the  exhaust  or,  in  other  words,  the  engine 
works  compound. 

Each  stem  between  the  operating  pistons  FF 
and  the  intercepting  valve  pistons  has  an  enlarge- 
ment B  (Figs.  175,  177  and  178)  which  fits 
loosely  into  a  chamber  of  the  intercepting  valve 
bushing  and  thus  forms  an  air  dash-pot,  thereby 
preventing  the  slamming  of  the  valves  when 
their  positions  are  changed. 

The  stem  of  the  piston  F  which  extends  back 
to  operate  the  reducing  valve  D  is  slotted  out,  as 
shown  in  Fig.  175,  so  as  not  to  engage  the  valve 
crank  K  (Fig.  174)  until  after  the  intercepting 


OPERATION  OF  COMPOUND  LOCOMOTI VE8.   139 

valve  has  closed  the  ports  EE.  Thus  the  live 
steam  used  in  the  low-pressure  cylinder  in  starting 
cannot  reach  the  high-pressure  side  through  the 
receiver  and  produce  a  back  pressure  on  the  high- 
pressure  piston. 

The  builders  state  that  in  case  of  accident  to 
either  side  of  the  engine,  the  opposite  side  may 
be  run  for  any  length  of  time  as  a  simple  engine 
by  disconnecting  and  blocking  the  injured  side  in 
the  same  manner  as  for  single-expansion  loco- 
motives. 


DICKSON    COMPOUND. 

The  Dickson  Locomotive  Works'  compound  is 
built  under  the  Dean  patents  which  cover  special 
valves  both  for  automatic  and  for  convertible 
compounds,  but,  inasmuch  as  the  practical  infor- 
mation is  based  on  the  mechanism  for  the  former 
class  only,  the  detailed  description  will  be  con- 
fined to  the  automatic  compound. 

The  starting  and  intercepting  valves  are  placed 
on  top  of  the  high-pressure  steam  chest  on  the 
right  side  of  the  engine.  Upon  opening  the  throt- 
tle for  starting,  live  steam  is  admitted  to  both 
cylinders,  but,  after  a  stroke  or  two,  the  inter- 
cepting valve  automatically  opens  and  the  engine 
works  compound  thereafter. 

The  high-pressure  exhaust  port  Q  (Fig.  179)  is  in 
the  balance  shield  of  a  Richardson  balanced  valve 
P,  having  its  top  removed,  and  thus  the  exhaust 
steam  from  the  high-pressure  cylinder  passes  up 
through  it  and  the  intercepting  valve  G  to  the 
receiver  and  low-pressure  cylinder,  when  the  in- 
tercepting valve  G  is  open.  Beneath  the  seat  R, 
intercepting  valve  G,  is  a  port  El  leading  to  the 
chamber  E.  • 

The  receiver,  as  usual  with  cross-compounds,  is 
located  in  the  smoke-box,  but  its  shape  is  out  of 
the  ordinary.  It  is  made  very  large  and,  between 
its  connections  with  the  high  and  the  low- 
pressure  saddles,  branches  into  two  forks,  each  of 
which  is  oval  and  has  metal  ribs  lengthwise  with 
the  pipes,  Fig.  180  shows  a  section  through  this 

(140) 


OPERATION  OF  COMPOUND  LOCOMOTIVE*.        141 


double  portion  of  the  receiver.  The  object  of  the 
designer  has  been  to  obtain  a  very  large  heating 
surface,  so  as  to  re-evaporate  some  of  the  water 


C/tesf 


condensed  in  the  high-pressure  cylinder  as  it 
passes  with  the  exhaust  steam  through  the  re- 
ceiver to  the  low-pressure  side.  From  the  re- 


142 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


ported  economy  of  these  engines,  it  would  seem 
that  the  object  has  been  largely  attained. 

Referring  to  Figs.  179  and  181,  it  will  be  seen 
that  the  intercepting  valve  G  is  fastened  to  the 
annular  stem  H  having  an  enlarged  top  above 
the  space  B  which  is  constantly  filled  with  air 
pressure  or  live  steam  from  the  pipe  C  when  the 
engine  throttle  is  open,  and  hence  sleeve  H  will 
be  found  at  the  top  of  its  travel,  as  illustrated, 
after  the  engine  has  started. 

The  operation  is  as  follows:  Open  the  throttle 
for  starting  and  live  steam  enters  the  high- 
pressure  steam  chest  from  the  induction  ports  7 

Fig.180. 


(Fig.  179)  as  usual  and  besides  has  a  connec- 
tion to  F  through  the  top  of  the  steam  chest,  as 
shown.  There  being  no  pressure  in  the  receiver 
(to  which  chamber  E  is  connected  through 
the  open  intercepting  valve  G\  the  weight  of 
N  will  have  caused  the  converting  valve  L 
to  drop  down,  and  thus  the  live  steam  passes 
through  valve  L  into  the  tube  AJ.  Port  K  ad- 
mits steam  to  the  enlarged  top  of  the  annular 
stem  H,  forcing  the  intercepting  valve  G  down  on 
its  seat  R  and  bringing  the  ports  D  in  the  stem  H 
opposite  the  ports  J  of  the  central  steam  tube  A, 
thus  admitting  live  steam  through  them  to  the 


OPERATION  OF  COMPOUND  LOGOMOTI  VEti.        143 

receiver  and  low-pressure  steam  chest.  With  the 
intercepting  valve  G  closed  (down),  the  first 
high-pressure  exhaust,  acting  in  chamber  E 
through  the  port  E1,  causes  piston  N  to  lift  and 
close  the  converting  valve  L  (as  shown  in  Figs. 
179  and  181),  thereby  shutting  off  the  supply  of 
steam  from  F  to  the  central  tube  AJ.  What 


steam  remains  in  this  tube  escapes  through  the 
relief  port  M  and  allows  the  intercepting  valve  G 
to  move  up  (open)  by  live  steam  pressure  from 
the  pipe  C  acting  in  the  annular  cavity  B,  as 
hereinbefore  described,  assisted  by  the  high- 
pressure  exhaust  below  G.  The  engine  then 
works  compound,  as  live  steam  is  shut  off  from 


144         ENGINEERS'  AXD  FIREMEN'S  MANUAL. 

the  low-pressure  cylinder  and  the  exhaust  from 
the  high-pressure  cylinder  takes  its  place. 

The  engine  above  described  is  an  automatic 
compound,  that  is;  starts  with  live  steam  in  both 
cylinders  but  after  the  first  stroke  changes  auto- 
matically to  compound. 

The  inventor  of  this  system,  in  a  design  not 
shown,  introduces  a  reducing  valve  in  the  central 
tube  A  and  adds  a  separate  exhaust  valve  operated 
by  live  steam  from  a  three-way  cock  in  the  cab, 
thus  making  a  compound  of  the  convertible  class, 
but  at  the  same  time  he  does  not  advise  convert- 
ible construction  in  compounds. 

Accidents  to  Dickson  Compounds. — What  should 
be  done  in  order  to  run  the  engine  in  with  the 
low-pressure  side  only  ?  Nothing  different  from 
a  simple  engine,  but  the  boiler  pressure  carried 
should  be  reduced  about  one-half  or  else  the 
engine  throttle  opened  very  slightly. 

How  could  the  engine  run  with  the  high-press- 
ure side  only?  There  being  no  means  of  exhaust 
except  into  the  receiver,  the  low-pressure  valve 
would  have  to  be  placed  so  as  to  uncover  the 
exhaust  port  or,  if  that  were  found  to  be  impos- 
sible, the  valve  entirely  removed. 


RHODE    ISLAND    COMPOUND. 

The  type  of  compound  locomotive  built  by  the 
Rhode  Island  Locomotive  Works  is  sometimes 
known  as  the  "Batchellor"  system,  that  being 
the  name  of  the  inventor  of  the  device. 

In  the  saddle  of  the  low-pressure  cylinder  on 
the  left  side  of  the  locomotive  is  located  an  inter- 
cepting and  a  reducing  valve  and  in  the  smoke- 
box  a  separate  high-pressure  exhaust  valve. 
When  the  throttle  is  opened,  the  engine  starts 
with  live  steam  in  both  cylinders.  With  the 
separate  exhaust  valve  closed  the  engine  auto- 
matically changes  to  compound  in  the  course  of 
a  complete  revolution;  with  it  open,  the  engine 
continues  to  work  as  a  simple  engine  as  long  as 
desired.  This  separate  exhaust  valve  is  operated 
at  the  will  of  the  engineer  by  means  of  a  three- 
way  cock  in  the  cab;  and  thus  the  engine  belongs 
to  the  class  of  convertible  compounds. 

Fig.  182  shows  a  vertical  section  lengthwise 
through  the  intercepting  valve,  with  the  latter  in 
the  position  when  the  engine  is  either  starting 
or  being  run  as  a  single-expansion  locomotive. 
Fig.  183  shows  the  same  section  with  the  inter- 
cepting valve  in  compound  position.  R  is  the 
receiver  port;  $  is  a  connection  from  the  main 
steam  pipe;  L  is  a  port  leading  to  the  low-press- 
ure steam  chest,  and  B  is  a  reducing  valve.  The 
intercepting  valve  is  composed  of  the  four  pistons, 
1,  2,  3  and  4,  of  which  the  last  works  in  an  oil 
dash-pot  C. 

(145) 


146        ENGINEERS'  AND  FIREMEN'S  MANUAL. 

If  the  engine  had  stopped  after  running  com- 
pound with  the  valve,  as  in  Fig.  183,  and  the  en- 
gine throttle  were  then  opened,  live  steam  from 
the  pipe  S  would  force  the  intercepting  valve 
into  simple  position  as  shown  in  Fig.  182,  because 
piston  2  is  larger  than  piston  7.  In  this  latter 
position  small  port  D  is  open  and  steam  from  S 
passes  through  it  and  the  reducing  valve  B  to 
the  low-pressure  side.  Piston  3  has  now  closed  the 
communication  with  the  receiver  R  in  which  one 


or  two  exhausts  from  the  high-pressure  cylinder 
soon  produces  sufficient  pressure  to  react  on  this 
piston  3,  bearing  the  intercepting  valve  to  the 
left  against  the  differential  pressures  on  pistons 
1  and  2  acting  in  the  opposite  direction,  and  the 
valve  is  shifted  to  compound  position,  as  in  Fig. 
183,  in  which  position  no  more  live  steam  can 
pass  through  port  D  to  the  low-pressure  side,  and 


OPERATION  OF  COMPOUND  LOCOMOTIVES.       147 

the  receiver  E  is  connected  through  port  L  with 
the  low-pressure  steam  chest,  for  which  it  forms 
the  supply  thereafter,  as  indicated  by  the  arrows. 

The  port  leading  from  the  live  steam  supply  8 
into  the  intercepting  valve,  is  larger  than  it 
appears  from  the  illustrations,  as  it  extends  partly 
around  the  circumference  of  the  valve. 

The  separate  exhaust  valve  shown  in  Figs.  184 
and  185  is  placed  on  the  receiver  in  the  smoke- 


box  and,  when  opened  by  pressure  through  pipe 
P  leading  from  a  three-way  cock  located  in  the 
cab  and  under  the  control  of  the  engineer,  con- 
nects the  receiver  with  the  main  exhaust  pipe. 
The  opening  of  this  valve  will  thus  permit  the 
high-pressure  exhaust  to  escape  and  there  will 
be  no  accumulation  of  pressure  in  the  receiver. 
Hence,  from  the  previous  explanation,  it  will  be 
seen  that  the  intercepting  valve  remains  in  sim- 


148 


ENGINEERS'  AND  FIREMEN'S  MANUAL. 


pie  position  (Fig.  182)  until  such  time  as  the 
engineer  closes  the  separate  exhaust  valve,  when 
a  stroke  of  the  engine  automatically  changes  the 
mechanism  to  compound  position,  as  before  de- 
scribed when  starting. 

The  operation  of  the  separate  exhaust  valve, 
shown  in  Figs.  184  and  185,  is  very  simple.  Press- 
ure admitted  from  the  cab  through  pipe  P, 
moves  the  valve  Ffrom  its  closed  position  (Fig. 
185)  to  the  right  and  vents  the  receiver  pressure 
direct  to  the  exhaust  pipe,  as  indicated  by  the 


-.185. 


Open  •JfnyineWar-TCiny/Sif/nple..     Closed-iZnyine  Compnn.  n 


arrows,  Fig.  184.  Withdrawing  the  pressure 
from  the  pipe  P,  allows  the  receiver  pressure  to 
automatically  move  and  hold  closed  the  valve  V, 
as  in  Fig.  185. 

Accidents  to  Rhode  Island  Compound.  —  If  it  be- 
came necessary  to  disconnect  either  side,  how 
should  the  engine  be  run  ?  Disconnect  properly, 
observing  the  same  precautions  advised  for  sim- 
ple engines,  then  open  the  separate  exhaust 


OPERATION  OF  COMPOUND  LOCOMOTIVES.       149 


valve  so  that  no  pressure  can  accumulate  in  the 


receiver/" 


What  would  you  do  with  a  broken  intercept- 
ing or  reducing  valve?  Open  the  separate  ex- 
haust valve  and  run  with  very  light  throttle,  or, 
preferably,  carry  a  reduced  boiler  pressure. 

Would  the  working  of  the  engine  be  affected 
if  the  separate  exhaust  valve  V  were  broken? 
Probably  not;  but,  if  it  left  an  opening  between 
the  receiver  and  the  exhaust,  the  engine  would 
run  as  a  simple  locomotive  only. 


*As  remarked  elsewhere  in  relation  to  designs  having  a  sep- 
arate exhaust  valve,  if  it  were  the  high-pressure  side  that  was 
disconnected,  it  would  not  be  necessary  to  open  the  separate  ex- 
haust valve  unless  there  was  some  leakage  of  steam  into  the 
receiver. 


THE  SCIENCE  OF  RAILWAYS, 

IN  TWELVE  VOLUMES. 
BY  MAESHALL  M.  KIEKMAN. 

REVISED    AND    ENLARGED    EDITION. 


SCIENCE  OF  BAIL  WAYS"  DESCRIBES  THE  METHODS 

AND  PRINCIPLES   CONNECTED  WITH  THE   EQUIPMENT, 

SHOPS,  ORGANIZATION,  LOCATION,  CAPITALIZATION, 

CONSTRUCTION,  MAINTENANCE,  OPERATION 

AND  ADMINISTRATION  OF  EAILROADS. 


This  great  work  is  everywhere  commended  for  its 
thoroughness,  vast  research  and  impartial  represen- 
tation. While  it  treats  of  specific  things,  it  does  not 
reflect  the  methods  of  any  particular  property  or  country. 
A  treasury  of  research  and  practical  experience,  it  por- 
trays truly  and  vividly  the  principles  and  practices  of 
the  great  art  of  transportation  in  their  highest  and  best 
forms.  It  is  popular  in  every  place  where  railroading 
has  reached  its  highest  development,  and  the  endorse- 
ment it  has  received  from  railway  men  of  the  highest 
attainments  is  conclusive  evidence  of  its  value  and  trust- 
worthiness. 


PUBLISHED  BY 

THE  WORLD  KAIL  WAY  PUBLISHING  COMPANY, 
CHICAGO,   ILL. 

(540) 


ORIGIN  AND  EVOLUTION  OF 
TRANSPORTATION." 


BY 
MARSHALL  M.  KIRKMAN. 


[NOTE. — The  first  chapter  in  this  volume  on  the  "  Evolution  of  Man,"  has 
been  incorporated  since  the  commendatory  notices  of  the  distinguished  men 
and  women  named  below,  were  written.  Originally  the  volume  embraced  only 
the  chapters  on  the  Ancients,  and  the  pictures  that  accompanied  the  same.] 


"For  originality  of  design  and  thorough  treatment  of  its  subject,  it  is 
unique  among  books.  Disraeli  would  have  enshrined  it  among  his  'Curi- 
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MCLAREN,  D.  D.,  D.  C.  L.,  Bishop  of  Chicago. 

"It  is  a  work  that  has  great  value  as  a  conspectus  of  the  nomadic  and 
other  tribes  of  men,  including  their  contrivances  for  locomotion.  It  fascin- 
ated me,  and  I  spent  the  evening  poring  over  its  wonderful  contents,  which 
are  most  instructive  as  well  as  curious.  Every  great  school,  and  every  college 
in  the  world,  should  possess  a  book  so  peculiar  and  the  result  of  so  much 
research."— Right  Reverend  A.  CLEVELAND  Cox,  D.  D.,  LL.D.,  late  Bishop  of 
Western  New  York. 

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of  New  York. 

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— His JSminence  JAMES  CARDINAL  GIBBONS,  D.  D.,  Archbishop  of  Baltimore. 

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of  St.  Paul. 


The  august  rulers  of  the  world  find  the  Portfolio  quite  as  fascinating  as 
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of  art  has  afforded  them.  Among  the  more  exalted  of  these  may  be  men- 
tioned Her  Most  Gracious  Majesty,  The  Queen  of  England,  and  His  Imperial 
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(541) 


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eral, Commanding  United  States  Army. 

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view."— WESLEY  MERBITT,  Major  General,  U.  S.  A. 

"  Mr.  Kirkman's  researches  have  taken  him  into  every  quarter  of  the  globe, 
and  among  every  race  of  man.  The  illustrations  depict  every  known  method 
of  carriage,  .  .  .  besides  pictures  of  ancients,  medieval  and  mythological 
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in  its  behalf."— MARY  LOWE  DICKINSON. 


(542) 


PARTICULARS  IN  REGARD  TO  THE  SALE,  DELIVERY, 
PAYMENT,  ETC.,  OF  THE 


SCIENCE  OF  RAILWAYS." 


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(548) 


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